WASHINGTON — North Korea fired an intercontinental ballistic missile on Tuesday that flew both higher and longer than previous such launches, a bold act of defiance against President Trump after he put the country back on a list of state sponsors of terrorism.
The president reacted cautiously to news of the launch, stating, “It is a situation that we will handle.”
But Defense Secretary Jim Mattis expressed greater concern, emphasizing what he said were technical advances on display in the 53-minute flight, which began when the missile was launched northeast of the capital, Pyongyang, and ended nearly 600 miles to the east, when it landed in the Sea of Japan.
“It went higher, frankly, than any previous shot they’ve taken,” Mr. Mattis said in the White House, where he was taking part in a budget meeting with the president and Republican congressional leaders.
“The bottom line is, it’s a continued effort to build a threat — a ballistic missile threat that endangers world peace, regional peace, and certainly, the United States,” the defense secretary said.
Experts said this latest launch — which landed west of the northern end of Honshu, Japan’s largest island — exhibited characteristics that underscored the increasing sophistication of North Korea’s program.
The missile flew higher and for a longer duration than two previous intercontinental ballistic missile launches, which flew for 37 minutes on July 4 and for 47 minutes on July 28.
David Wright, a scientist at the Union of Concerned Scientists, said the missile performed better than the two fired in July, and exhibited a potential range of more than 8,000 miles, able to reach Washington or any other part of the continental United States.
“It’s pretty impressive,” Dr. Wright said of the test flight. “This is building on what they’ve done before. It’s muscle-flexing to show the U.S. that they’re going to continue to make progress.”
However, Dr. Wright noted that in an effort to increase the vehicle’s range, the North Koreans might have fitted it with a mock payload that weighed little or next to nothing. So the distance traveled, while impressive, does not necessarily translate into a working intercontinental ballistic missile that could deliver a thermonuclear warhead.
For all the evidence of technical advancements, a senior White House official said the significance of the launch should not be overstated, given the number of missile tests North Korea has carried out this year. The White House had expected some form of retaliation after it put the North back on its list of state sponsors of terrorism last week.
Mr. Trump, officials said, will stick to his policy of rallying nations to apply economic pressure on North Korea, backed up by the threat of military action. In a statement, Secretary of State Rex W. Tillerson condemned the launch. But he added, “Diplomatic options remain viable and open, for now.”
The launch came in the middle of the night on the peninsula, with less advance warning, according to experts. Aerial photographs of North Korean launch sites did not show missiles waiting on launchpads to be fueled, although Japanese officials had reported that radio telemetry pointed to a possible launch.
Some experts theorized that North Korea was now fueling missiles horizontally, before they are placed on the launchpad. In the past, it went through a lengthier process of rolling a missile onto a launchpad, filling it with liquid fuel and then launching it — steps that could take days.
“This shortens the time from when they become visible to when they go in the air, and makes it less likely that the U.S. will be able to strike before it launches,” said Rodger Baker, a vice president of strategic analysis with Stratfor, a geopolitical risk analysis company.
American officials offered no proof of the horizontal fueling theory, but they acknowledged that North Korea is searching for ways to get around the United States’ ability to mount a pre-emptive strike.
Mr. Mattis noted that South Korea had fired several “pinpoint missiles” into the water after the launch “to make certain North Korea understands that they could be taken under fire by our ally.”
Although it was the third time that the South had fired missiles in response to a North Korean missile test, this response was more muscular, officials said, with South Korea firing from a land-based missile battery, a Navy destroyer and an F-16 fighter jet. It was meant to show that the South had multiple ways of hitting a North Korean missile on the launchpad in a pre-emptive strike, according to South Korean military officials.
After the launch, the United Nations Security Council scheduled an emergency meeting on the issue for Wednesday afternoon.
Matthew Rycroft, Britain’s ambassador to the United Nations, told reporters that the launch appeared to be “yet again, a reckless act by a regime which is more intent on building up its ballistic missile nuclear capability than it is on looking after its own people.”
President Moon Jae-in of South Korea and Prime Minister Shinzo Abe of Japan each called meetings of their national security councils to discuss the North’s latest provocation. Mr. Trump called both leaders on Tuesday, at their request, according to the White House.
Unlike the launches over the summer, when the missiles flew over Japan’s northern island, Hokkaido, the government did not issue cellphone alerts to warn its citizens.
In Washington, a spokesman for the Defense Department, Col. Robert Manning of the Army, said that the launch “did not pose a threat to North America, our territories or our allies,” and added that the American commitment to the defense of South Korea and Japan “remains ironclad.”
Mr. Trump, who has in the past insulted North Korea’s leader, Kim Jong-un, and threatened “fire and fury” that would “totally destroy” that country, avoided threats of military retaliation against the North on Tuesday. But he did not hesitate to use the specter of a military confrontation in Asia as leverage against the Democrats in the budget wars in Washington.
The missile launch, he predicted, would “have a huge effect on Schumer and Pelosi,” referring to Senator Chuck Schumer of New York and Representative Nancy Pelosi of California, the chambers’ Democratic leaders, both of whom boycotted his budget meeting.
“If you look at the military, we want strong funding for the military,” Mr. Trump said. “They don’t.”
North Korea has persisted in its nuclear weapons and missile development despite nine rounds of sanctions that the Security Council has imposed since its first nuclear test in 2006.
This year, the North has increased the frequency and daring of its missile tests, sending two missiles over Japan in August and September, while demonstrating technical progress that suggested it had developed the ability to strike the continental United States.
In the wake of a Sept. 3 underground nuclear test — the sixth by North Korea — the United Nations Security Council imposed a new round of sanctions against the country.
In the nearly three months since that test, as leaders of North Korea and the United States have exchanged insults, the world has braced for another show of force by the North.
Mr. Trump warned that if North Korea threatened the United States or its allies, Washington would have “no choice but to totally destroy North Korea,” and he mockingly referred to Mr. Kim as “rocket man.”
Mr. Kim responded by calling Mr. Trump “a mentally deranged U.S. dotard,” and his foreign minister later warned that Mr. Kim could order the test of a hydrogen bomb over the Pacific.