North Korea fired a missile on Aug. 29 that flew over Japan and landed in the Pacific Ocean. (Reuters)

North Korea launched a ballistic missile Tuesday morning that flew over the northern Japanese island of Hokkaido, the most brazen provocation of Kim Jong Un’s five-year-long rule and one that elicited strong condemnation from U.S. allies Japan and South Korea.

The launch poses a further challenge, in particular, to President Trump, who has made North Korea a favorite rhetorical target. Trump said earlier this month that he would make Kim “truly regret” harming the United States or its allies.

In Japan, the prime minister was visibly agitated by North Korea’s actions. “A missile launch across Japan is an outrageous act that poses an unprecedented, grave and serious threat, and significantly undermines the peace and security of the region,” Shinzo Abe said after an emergency national security council meeting.

Japan’s upgraded missile response system swung into action, sending emergency alerts through cellphones and over loudspeakers shortly after 6 a.m., warning people on the potential flight path of the threat and advising them to take cover. 

However, Japan did not try to shoot down the missile.

Japanese Prime Minister Shinzo Abe said the Japanese government would take ‘all possible measures’ to ensure the safety of his people after a North Korean missile was fired over Japan on Aug. 29. (NHK)

The missile appears to have been a Hwasong-12, the inter­mediate-range ballistic missile technically capable of flying 3,000 miles that North Korea has been threatening to launch toward the U.S. territory of Guam.

But North Korea launched Tuesday’s missile to the east, over Hokkaido and into the Pacific Ocean, rather than on a southward path toward Guam, apparently to test its flight on a normal trajectory without crossing a “red line” of aiming at the United States.

Still, this launch, coming after North Korea last month launched two intercontinental ballistic missiles theoretically capable of reaching the U.S. mainland, underscore both Kim’s defiance of the international community and his determination to press ahead with his missile program. Kim has now ordered the launch of 18 missiles this year alone, compared with the 16 missiles his father, Kim Jong Il, fired during 17 years in power.

The White House did not immediately respond to the latest provocation, but the Japanese prime minister’s office said Trump and Abe talked by phone for 40 minutes after the launch, agreeing that the test was unprecedented and that they should further increase the pressure on North Korea. 

The the U.N. Security Council confirmed it would hold an emergency meeting in New York Tuesday to discuss the latest provocation. Missile launches and nuclear tests are banned by the U.N. Security Council, but North Korea has paid no attention to its resolutions.

In Seoul, President Moon Jae-in, a liberal who has promoted engagement with Pyongyang, ordered an “overwhelming show of force” in response to the missile launch. South Korea’s military aircraft dropped eight bombs on a shooting range on the southern side of the border with North Korea.

Analysts said Tuesday’s launch marked a worrying escalation from North Korea. “This is a much more dangerous style of test,” said Abraham Denmark, director of the Asia program at the Wilson Center and a former top East Asia official at the Pentagon.

How three recent launches signaled new leaps in North Korea’s missile capabilities

North Korea’s recent missile tests had been carefully calibrated to go nearly straight up and land in the sea between the Korean Peninsula and Japan, rather than overflying Japan.

“North Korean missiles have a habit of breaking apart in flight, so if this happened and parts of it landed in Japan, even if it was not North Korea’s intention, this would amount to a de facto attack on Japan,” Denmark said.

This missile appeared to have broken into three during flight, but all of the parts landed in the sea.

The missile was launched at 5:58 a.m. Japan time from a site at Sunan, north of Pyongyang and the location of the country’s main international airport.

U.S. intelligence agencies were monitoring the site and had seen signs of the impending launch hours earlier, when they spotted Hwasong-12 missile equipment being moved into place.

The Hwasong-12, known to American agencies as the KN-17, is fired from a road-mobile launcher — usually a modified truck — making it easy to move around the country and launch on short notice.

North Korea has sent rockets over Japan before, in 1998 and again in 2009. But both times it claimed that they were satellite launches, and in the second case, it gave Japan notice before the launch. 

This time, there was no notice, and analysts said that this launch was clearly for military purposes.

The missile traveled almost 1,700 miles in total, flying over Hokkaido at 6:06 a.m. before landing in the Pacific Ocean 730 miles to the east of Hokkaido’s Cape Erimo at about 6:12 a.m. During this time, it traveled through Japanese airspace for about two minutes, government officials said.

The Pentagon said it had detected the launch but was still in the process of assessing it.

Japanese military aircraft and ships headed to the landing site on Tuesday morning to try to recover debris from the missile, which could yield important information about its technical capabilities.

The Japanese broadcaster NHK showed Patriot missiles installed at sites around the country. 

“We will make every possible effort to protect citizens’ lives and property,” Abe told reporters before heading into the national security council meeting.

However, the Japanese military did not attempt to intercept the missile. Government officials said they could tell the missile was heading into the sea, rather than toward Japanese territory.

But analysts said that the PAC-3 missile defense system has a range of less than 20 miles and is designed to intercept the missile as it’s coming down, meaning that even the batteries on Hokkaido would not have been able to intercept this one.

Tuesday’s launch, on the heels of three short-range missiles fired Saturday, comes amid ongoing joint exercises between the United States and South Korean militaries, exercises that North Korea always strongly protests because it considers them preparation for an invasion. 

The exercises, which mainly involve computer simulations rather than battlefield maneuvers, are due to end Thursday.

“We should expect a kinetic reaction from North Korea during the exercises, but this pushes the boundaries of an ordinary response,” said Daryl Kimball, the director of the Arms Control Association.

However, Kimball said that talks still remain the best course of action for dealing with North Korea.

“The U.S. and Japan have so few options to respond to these ballistic missile tests short of negotiations that would have North Korea agree to halt these launches in return for a modification of future military exercises,” he said. “This is why North Korea is such a problem — there are no good options.”

Despite the international pressure, Kim has pressed ahead unrelentingly with his missile program.

His government had been threatening to fire a missile to pass over Japan and land near Guam, which is home to two huge U.S. military bases, by the middle of this month. However, Kim later said that after reviewing the plans, he would “watch the Yankees a little longer” before making a decision about whether to launch.

After the Guam threat, Trump warned North Korea that “things will happen to them like they never thought possible” should the isolated country attack the United States or its allies.

With no missile launches during the first three weeks of August, the Trump administration had suggested that its tough talk was working, with Trump saying last week at a rally in Phoenix that Kim had come to “respect” him.

John Wagner and Ellen Nakashima in Washington and Yuki Oda in Tokyo contributed to this report.