This was the second time in less than three weeks that North Korea sent a ballistic missile over Japan, and the launch came less than two weeks after North Korea exploded what was widely believed to be a hydrogen bomb.
The latest launch immediately sparked angry reactions from Tokyo and Seoul. Secretary of State Rex Tillerson said the international community had to unite to punish Kim Jong Un's regime, calling this week's U.N. Security Council sanctions "the floor, not the ceiling."
"China supplies North Korea with most of its oil. Russia is the largest employer of North Korean forced labor," Tillerson said in a statement, naming the two veto-wielding members of the Security Council that are also the closest thing to allies that North Korea has.
"China and Russia must indicate their intolerance for these reckless missile launches by taking direct actions of their own," he said.
The missile was launched from the Sunan airfield just north of Pyongyang about 6:30 a.m. local time, South Korea's Joint Chiefs of Staff said. It flew 2,300 miles over 17 minutes, passing over Hokkaido and landing some 1,200 miles to the east in the Pacific Ocean.
The launch immediately triggered emergency alerts in Japan, with text messages and loudspeakers telling residents beneath the missile's potential flight path to seek shelter.
The Japanese government warned people not to approach any debris or other suspicious-looking material, a reflection of the fact that North Korean missiles sometimes break up in flight.
Echoing Tillerson, Japanese Prime Minister Shinzo Abe said that the international community must "firmly unite to send out a clear message" to Pyongyang. "We need to have North Korea understand that they will have no bright future if they keep going this way," he said.
But Japan did not try to shoot down the missile. South Korea, however, immediately fired two of its Hyunmoo-II missiles 155 miles into the sea — the same distance they would have had to travel to reach the Sunan airfield.
In Seoul, South Korean President Moon Jae-in, who has been staunchly in favor of engagement with North Korea, said that dialogue was "impossible in a situation like this."
In Washington, the White House said President Trump was briefed on the latest North Korean missile launch by his chief of staff, John F. Kelly.
The missile did not pose a threat to North America or to the U.S. territory of Guam, the U.S. Pacific Command said. The Pacific island of Guam is home to large Air Force and Navy bases and was the target of recent rhetorical threats from North Korea.
"We continue to monitor North Korea's actions closely," the Pacific Command said in a statement.
In Beijing, Hua Chunying, a spokeswoman for the Chinese Foreign Ministry, told reporters Friday that China opposed the test, but she called the situation on the Korean Peninsula "complicated, sensitive and severe" and urged all sides to exercise restraint.
The Global Times, a Chinese Communist Party-controlled tabloid known for its nationalist tone, said in a Friday editorial that, although North Korea is the troublemaker, it is the United States and South Korea that can change the status quo.
"North Korea's current nuclear and missile activities seem unstoppable, the channel for resolving the problem via negotiation is still missing," the editorial read.
David Wright, co-director of the global security program at the Union of Concerned Scientists, said the latest missile launch was worrying.
"The range of this test was significant since North Korea demonstrated that it could reach Guam with this missile," he said, although he noted it is not known whether the missile was carrying a payload, something that influences range. Guam lies 2,100 miles from North Korea, well within technical reach of the intermediate-range missile.
Friday's launch appeared similar to the previous launch, on Aug. 29. On that day, North Korea fired a Hwasong-12 — an intermediate-range ballistic missile technically capable of flying 3,000 miles, enough to reach Guam — from the Sunan airfield. But it also flew to the east, over Hokkaido and into the Pacific Ocean, rather than southward toward Guam.
Analysts said that after testing its missiles by firing them straight up and having them crash into the sea between the Korean Peninsula and Japan, North Korea was apparently testing its missiles' flight on a normal trajectory without crossing a "red line" of aiming at the United States.
On Thursday, a North Korean state agency had issued an alarming threat to what it offensively called the "wicked Japs."
"The four islands of the [Japanese] archipelago should be sunken into the sea by [our] nuclear bomb," a spokesman for the Korea Asia-Pacific Peace Committee said in a statement carried by the official news agency. Hokkaido is the northernmost of Japan's four main islands.
"Japan is no longer needed to exist near us," the committee spokesman said.
This is the first missile launch since North Korea conducted a huge nuclear test Sept. 3, which analysts say appeared to live up to Pyongyang's claim that the device involved was a hydrogen bomb, exponentially more powerful than a normal atomic device.
That test, combined with the rapid pace of missile launches and North Korea's stated goal of wanting to be able to strike the mainland United States with a nuclear-tipped missile, has caused alarm around the world.
The U.N. Security Council imposed its toughest sanctions to date against North Korea on Monday, setting limits on its oil imports and banning its textile exports. But the new sanctions were a compromise. To win the support of China and Russia, the United States had to tone down its demands, which included a total oil embargo and a global travel ban on Kim.
Tillerson's statement reflected the Trump administration's frustration with the reluctance of Beijing and Moscow to inflict real pain on Pyongyang.
The North Korean statement that lashed out at Japan on Thursday also displayed Pyongyang's anger at what it called the "heinous sanctions resolution."
The North Korean people and military wanted "the Yankees, chief culprit in cooking up the 'sanctions resolution,' [to] be beaten to death as a stick is fit for a rabid dog," said the committee statement delivered through the spokesman.
The Sept. 3 nuclear test, North Korea's sixth, is now widely assumed to have been a test of a hydrogen bomb, as Pyongyang claimed in its state propaganda.
The Japanese government estimates that the force of that explosion was 160 kilotons — more than 10 times the size of the bomb dropped on Hiroshima in 1945 — but some analysts have said its yield could have been as much as 250 kilotons.
U.S. Defense Secretary Jim Mattis, traveling from Washington to view U.S. nuclear weapons at Minot Air Force Base, N.D., said Wednesday that the North Korean nuclear test appeared to be "100 kilotons or more."
"It's a large one," he said.
Earlier, Air Force Gen. John Hyten, chief of U.S. Strategic Command, said that he "had to assume" that North Korea had probably tested a hydrogen bomb, judging by the size of the explosion.
Speaking just before the North's latest missile launch, Hyten, who oversees U.S. nuclear forces and monitors North Korea, told reporters that the size, yield and other indications in North Korea's most recent nuclear test "equates to a hydrogen bomb."
He said he could not confirm that a hydrogen bomb was tested but said the test was significant "because of the sheer destruction and damage you can use and create with a weapon of that size."
"The change from the original atomic bomb to the hydrogen [bomb] changed our entire deterrent relationship with the Soviet Union," Hyten said. "It is significantly of concern not just to Strategic Command but to everybody in the free world. It should be of concern to people in the neighborhood, which is Japan and Korea, as well as China and Russia."
Hyten said that if North Korea can mount a bomb of that power on a missile, it could potentially destroy a city. The United States has the ability to deter a nuclear attack on itself or its allies because of the nuclear weapons it maintains, Hyten said, but it's a "different question" whether the United States can stop North Korea from building nuclear weapons.
Hyten said that the United States still has not seen North Korea "put everything together" with a nuclear warhead mounted on an intercontinental ballistic missile but that it is only a matter of time before the North Koreans do so.
"Whether they have the ability, I don't have any insight into that," Hyten said. "I can just look at historic examples and say that it could be within months or it could be within years."
Lamothe reported from Offutt Air Force Base in Nebraska. David Nakamura in Washington and Luna Lin and Shirley Feng in Beijing contributed to this report.