Officials said the North fired the barrage at around 7:34 a.m. Japan time from near North Korea’s Donchang-ri long-range missile site.

The Defense Ministry said they flew about 1,000 km and reached a height of about 260 km, with three of the missiles falling within Japan’s exclusive economic zone, 300 km to 350 km west of the Oga Peninsula in Akita Prefecture. The fourth missile fell near the EEZ, which extends 200 nautical miles (370 km) from Japan’s coastline.

During Monday’s Upper House Budget Committee session, Abe condemned the provocation as “utterly intolerable” and noted the North’s accelerating technological advancements.

“(The test-firing) clearly shows that North Korea is now a new level of threat,” Abe said.

The prime minister also said that “Japan will continue to coordinate closely with the United States, South Korea and other countries to strongly urge North Korea to exercise restraint.”

Although this is not the first time that North Korean missiles have fallen within Japan’s EEZ, a high-ranking official said that because four missiles were apparently fired simultaneously from the same location, the move represents a grave danger to Japan’s national security. In September, the North fired three ballistic missiles that also fell within Japan’s EEZ, some 200 km to 250 km off Okushiri Island, Hokkaido.

Monday’s salvo prompted officials in Tokyo to hold a National Security Council meeting to discuss responses.

After the NSC meeting, Chief Cabinet Secretary Yoshihide Suga said the government had already lodged protests with Pyongyang — using the “strongest terms” — through the embassy in Beijing. Suga added that it is natural that the international community will seek even tougher responses given that the North has ignored numerous United Nations resolutions.

Following the launch, Kenji Kanasugi, head of Asian and Oceanian affairs in the Foreign Ministry, and Joseph Yun, U.S. special representative for North Korea policy, confirmed by telephone that they will closely coordinate bilaterally as well as multilaterally with South Korea and the U.N. to urge North Korea to halt further provocations.

South Korea is likely to intensify its push to isolate the North diplomatically by seeking its suspension from global bodies such as the U.N.

“After completing an analysis and assessment of the North’s missile tests, the government will likely come out with a much tougher countermeasure with regards to such issues as suspending the North’s membership in the U.N.,” the Yonhap news agency quoted an anonymous South Korean government official as saying.

The test could also add momentum to calls by U.S. lawmakers to return Pyongyang to a list of state sponsors of terrorism.

Monday’s barrage came as Pyongyang continues to show off its advances in nuclear weapons and missile technology. Less than three weeks ago, the North defiantly test-fired a new type of medium-range missile that is believed to use solid fuel. The launch came during Abe’s first summit talks with U.S. President Donald Trump.

Experts say solid-fueled missiles represent more of a threat than their liquid-fueled counterparts as they requires less preparation time.

There has been growing speculation that the North will conduct an intercontinental ballistic missile (ICBM) test after Kim Jong Un used a New Year’s Day address to claim that Pyongyang was in the final stages of developing a long-range missile capable of hitting New York and Washington. South Korea’s military said Monday that none of Monday’s missiles appeared to have been ICBMs.

Experts agreed, saying that the launch appeared to be similar to ones conducted last year.

“Although we cannot be 100 percent certain what type of missiles were fired until we get images from KCNA, the range and apogee would indicate they are closer to an extended range Scud or Rodong missile used in a salvo launch,” said David Schmerler, a researcher at the Center for Nonproliferation Studies at the Middlebury Institute of International Studies. “We saw launches like this last year off of Reunification Highway near Hwangju.”

Sebastian Maslow, an assistant professor of political science at the Tohoku University School of Law in Sendai, said it’s too early to determine what the launches mean in terms of the North’s quest to field a missile capable of hitting the continental U.S.

“I would not jump to any conclusion as to what this missile launch suggests with regard to the DPRK’s ICBM program, but (rather it appears to be) a test of U.S., Japan and ROK response capabilities detecting and projecting the missile’s trajectory, intelligence sharing, and coordination of any likely response,” Maslow said, using the acronyms for the two countries’ formal names, the Democratic Republic of Korea and the Republic of Korea.

The timing of the launches also raised questions among regional observers.

They overlapped with annual South Korean-U.S. military exercises known as Foal Eagle, drills that Pyongyang regards as a prelude to invasion. The launches also came right after the opening of China’s rubber-stamp parliament in Beijing — a gathering aimed at highlighting President Xi Jinping’s command over foreign and domestic affairs.

“We may speculate that the launches may be intended to test China’s further willingness of confronting the DPRK” as the Communist Party’s leadership gathers for its annual meeting, Maslow said.

For Abe, the timing of the missiles’ splashdown in Japan’s EEZ appeared fortuitous. The prime minister has been grappling with a scandal surrounding a nationalist kindergarten’s shady land deal that is allegedly linked to his office.

The launch, Maslow said, could help Abe shift attention from the scandal to national security issues.

“No doubt, Abe and his Liberal Democratic Party will amplify the DPRK missile and nuclear program and North Korea threat narrative in the coming days and weeks to highlight the importance of U.S.-Japan security cooperation, and the need to expand Japan’s missile defense program, including THAAD (Terminal High Altitude Area Defense system) as part of the bilateral security framework.”

The U.S.-made THAAD system is due to be deployed to South Korea later this year. Japan is also reportedly considering bringing in the system.

Monday’s launch also came as the Trump administration is reportedly considering a harder-line approach to the North’s provocations. Trump’s national security deputies have reviewed in recent meetings a range of options to counter the North’s missile threat, The New York Times reported Sunday. Options include direct missile strikes on its launch sites and the possibility of reintroducing nuclear weapons to the South, The Times said.

Those options will soon be presented to Trump and his top national security aides, the report said, quoting U.S. administration officials.

In Washington, the State Department condemned the launches, vowing that the U.S. was ready to “use the full range of capabilities at our disposal against this growing threat.”

“We remain prepared — and will continue to take steps to increase our readiness — to defend ourselves and our allies from attack, and are prepared to use the full range of capabilities at our disposal against this growing threat,” acting spokesman Mark Toner said in a statement.

The test-firing also occurred amid growing international pressure on Pyongyang after the assassination of North Korean leader Kim Jong Un’s half brother Kim Jong Nam, who was allegedly killed by Indonesian and Vietnamese women using the deadly VX nerve agent. It is widely speculated that the Kim Jong Un himself ordered the assassination.

“The North probably wants to deflect the international attention on this issue with the test-fire, as it has denied its involvement in the assassination,” said Hideshi Takesada, a professor at Takushoku University and an expert on North Korea.

The international community has been piling pressure on the North after it conducted two nuclear tests and launched 23 missiles last year — almost twice as many as it did under the rule of Kim Jong Un’s father, Kim Jong Il.

The U.N. last year adopted what Japanese officials call “the toughest sanctions” to date against North Korea, including a ban on coal imports from the country.

The efficacy of the sanctions, however, largely depends on China, which is Pyongyang’s biggest economic partner. Beijing announced last month that it was halting coal imports from the North until the end of this year.

“We will have to see how Japan and the rest of the international community reacts, but my feeling is that looking at all the recent developments … Japan and others will have to find some way to take defensive measures and impose costs on North Korea,” said Daniel Pinkston, an East Asia expert at Troy University in Seoul.

“In my view, failure to do so invites more North Korean belligerence. … THAAD and more missile defense cooperation by Japan should be expected,” he added.

Information from Kyodo added 

A teleconference between the two leaders followed a report by the state-owned Korean Central News Agency earlier Tuesday that the missile launch drill was targeting U.S. military bases in Japan.

The North is said to be hoping to drive a wedge between the U.S. and Japan, but the two leaders emphasized the Japan-U.S. alliance was solid and the U.S. was committed to the security of Japan.

“The fact that it did not take long for the leaders of Japan and the U.S. to hold a conversation after yesterday’s missile test proves that the U.S. and Japan are always together,” Abe told reporters after he spoke with Trump for 25 minutes.

“President Trump said that the U.S. won’t tolerate the provocation by the North and that the U.S. is 100 percent with Japan. He also asked me to deliver his message to the Japanese people.”

Abe said that the U.S. made clear that every option is on the table, and that the North has to be deterred from further provocations. The leaders also demanded that North Korea abide by U.N. resolutions to cease and dismantle its nuclear weapons program.

Following the Abe-Trump conference, Defense Minister Tomomi Inada also held a teleconference with U.S. Defense Secretary James Mattis and South Korean Defense Minister Han Min-koo. The three defense chiefs agreed that both bilateral and trilateral consultations were critical to respond to the threat from the North.

Mattis also told Inada that the U.S. will use every option, including extended deterrence, to defend Japan — a position he highlighted during his visit to Japan last month.

In a bid to up pressure on the North, Foreign Minister Fumio Kishida said the three countries were working together to convene the United Nations Security Council to address the latest missile launch.

“It is important to urge member countries to abide by the resolution to decisively impose sanctions against the North,” Kishida said after a Cabinet meeting on Tuesday.

Japan and the U.S. also agreed to hold a “two-plus-two” meeting of their foreign and defense ministers as soon as possible. Mattis has already visited Japan, coming last month, while U.S. Secretary of State Rex Tillerson is scheduled to visit later this week, with the U.S. position on North Korea likely to be discussed.

Abe’s conversation with Trump, whose administration is mulling its strategy against the North, came less than three weeks after a summit between the pair in Washington.

While Abe said it was critical to share the two nations’ strategic objectives on the matter, it was still unclear what exactly Trump’s North Korea strategy would be as he was yet to announce the political appointees who would be in charge of Northeast Asia policy.

Trump appears to be steadfastly against the North and critical of the so-called strategic patience espoused by former U.S. President Barack Obama, where the U.S. would not engage in any dialogue until the North decides to denuclearize.

The New York Times reported on Sunday that the Trump administration was reportedly considering options including direct missile strikes on North Korean launch sites and reintroducing nuclear weapons in South Korea.

“This underscores the importance of getting the national security apparatus in working order quickly,” said Brad Glosserman, executive director of the Pacific Forum CSIS, a Honolulu-based think tank. “The president needs a national security adviser to run the process and get actionable advice to the president. If that doesn’t happen, other countries will recognize the gap and try to exploit it.”

Tetsuo Kotani, a senior fellow at the Japan Institute of International Affairs, said the North was trying to destabilize the Japan-U.S. alliance by showing it was capable of striking U.S. military bases here.

“This is nuclear blackmail by the North,” he said. “They are sending the message that they will target Japan if it provides support to the U.S., aiming to make Japan uneasy. In this way, Pyongyang is trying to drive a wedge between Japan and the U.S.”

Despite Pyongyang ratcheting up its rhetoric toward Tokyo and Washington, J. Berkshire Miller, a Tokyo-based international affairs fellow with the Council on Foreign Relations, said such a strategy might not be working.

“This adds another element to Japan’s threat perceptions — with three missile parts landing in Tokyo’s EEZ (exclusive economic zone) — on the North and only hurts Pyongyang’s aim of weakening U.S. alliances in the region,” he said. “If anything, provocations like this only strengthen the purpose and resolve of enhanced trilateral cooperation between Washington, Seoul and Tokyo.”

Abe made the remark to the security committee of the Upper House when asked about a proposal by his ruling Liberal Democratic Party to have Japan pursue the capability to directly attack North Korean military bases.

Abe emphasized that Tokyo has no plan to acquire such powerful weapons and would never launch a pre-emptive strike against any country.

But the government at the same time should conduct “various studies” for defense and strengthen the Japan-U.S. military alliance, Abe said.

“It’s possible that North Korea has the ability to hit (Japan) with a ballistic missile carrying sarin in its warhead,” he said.

He also noted that “nearly 100 innocent people, including children and babies, were victimized” by chemical weapons in Syria.

“We need to squarely look at a reality like that, and firmly maintain the deterrence power to not let such things happen” to Japan, Abe said.

The South Korean Defense Ministry has estimated that Pyongyang, which reportedly started producing chemical weapons in the 1980s, now owns 2,500 to 5,000 tons of chemical weapons, including the lethal nerve agents sarin and VX.

At a news conference later in the day, Chief Cabinet Secretary Yoshihide Suga said Tokyo believes North Korea has “multiple numbers of plants” producing chemical weapons and possess “considerable amount” of them.

Abe’s remark follows on the heels of a Kyodo News report that said U.S. President Donald Trump promised Abe during a telephone discussion earlier this month to consult with Japan before taking action — including military action — against North Korea.

Quoting bilateral diplomatic sources, the report Wednesday said Trump also indicated to Abe that the United States will tighten sanctions on Chinese firms doing business with North Korea if China does not cooperate in addressing the threat presented by Pyongyang’s nuclear and missile programs.

That suggests Trump is prepared for active involvement in blocking further provocations by Pyongyang while at same time mindful of U.S. ally Japan, which has significant concerns about a potential U.S. attack on North Korea, the report said.

In telephone conversations on April 6 and Sunday, the leaders agreed that North Korea’s nuclear tests and repeated ballistic missile launches posed a grave security threat and affirmed that they will work together with South Korea on the matter.

According to the report, Trump showed Abe that he understands the risks Japan would face from a crisis on the Korean Peninsula. Abe said he highly appreciates Trump’s assertion that all options are on the table in dealing with North Korea.

While telling Abe the United States stands with Japan “100 percent,” Trump signaled his intention to consult with Japan before taking action on the North, the report said.

It also said the president sought Abe’s agreement with his administration’s security and diplomacy doctrine of “peace through strength” — an about-face from the “strategic patience” approach of his predecessor, Barack Obama, toward the reclusive state.

Ahead of the discussions, the Japanese government had requested the United States first discuss with Japan at the working level before mounting any attack on North Korea, out of fear that retaliation would directly affect Japan’s security, the report said.

The leaders also confirmed the necessity of urging China to get more involved in dealing with the North, it said.

After his summit last week with Chinese President Xi Jinping, Trump shared with Abe that he had told the Chinese leader that Washington has not ruled out taking unilateral action if no concrete moves are made toward de-nuclearizing Pyongyang, the report said.

The United States has fresh economic sanctions ready for the North, including asset freezes and stronger sanctions on Chinese firms that do financial transactions with the hermit state, Trump said according to the report.