North Korea has abruptly ended a 10-week pause in its weapons testing by launching what the Pentagon said was an intercontinental ballistic missile, possibly its longest-range test yet, a move that will escalate already high tensions with Washington.
Pentagon spokesman Colonel Rob Manning said the missile was launched from Sain Ni, North Korea, and travelled about 620 miles before landing in the Sea of Japan within 200 nautical miles of Japan's coast.
It flew for 53 minutes, Japan's defence minister said.
South Korea, a key US ally separated from the North by a highly militarised border, responded with shorter-range missile tests of its own to mimic striking the North Korea launch site, which it said lies not far from the North Korean capital.
The launch is North Korea's first since it fired an intermediate range missile over Japan on September 15, and it appeared to shatter chances that the hiatus could lead to renewed diplomacy over the reclusive country's nuclear programme.
US officials have sporadically floated the idea of direct talks with North Korea if it maintained restraint.
An intercontinental ballistic missile test is considered particularly provocative.
It would signal further progress by Pyongyang in developing a weapon of mass destruction that could strike the US mainland, which President Donald Trump has vowed to prevent, using military force if necessary.
In response to the launch, Mr Trump said the United States will "take care of it".
He told reporters: "It is a situation that we will handle."
He did not elaborate.
White House press secretary Sarah Sanders tweeted that Mr Trump was briefed on the situation "while missile was still in the air."
Col Manning, the Pentagon spokesman, said the North American Aerospace Defence Command, known as Norad, "determined the missile launch from North Korea did not pose a threat to North America, our territories or our allies".
US scientist David Wright said that based on initial reports on the altitude and duration of the test, it appeared to be North Korea's longest-range test yet.
If flown on a standard trajectory rather than at a lofted angle, the missile would have a range of more than 8,100 miles, said Mr Wright, a physicist at the Union for Concerned Scientists.
A week ago, the Trump administration declared North Korea a state sponsor of terrorism, further straining ties between governments that are still technically at war.
Washington also imposed new sanctions on North Korean shipping firms and Chinese trading companies dealing with the North.
North Korea called the terror designation a "serious provocation" that justifies its development of nuclear weapons.
Echoing the initial US assessment, Japan's defence minister Itsunori Onodera said the missile was likely an intercontinental ballistic missile.
He said it was launched on highly lofted trajectory and reached a high point exceeding 2,400 miles, exceeding the height of previous missile tests.
He said it flew for about 53 minutes.
"We can assume it was ICBM-class," Mr Onodera said.
Seoul's Joint Chiefs of Staff said the US and South Korean militaries were analysing the launch data from the missile.
They said it travelled a distance of 600 miles and estimated the apogee at 2,796 miles.
In response to the North Korean test, it said South Korea conducted a "precision-strike" drill, firing three missiles, including one with a 620-mile range, to accurately hit a target that stood for the North Korean launch site.
South Korea's presidential office said it was holding a National Security Council meeting on Wednesday morning local time to discuss the launch.
Japanese prime minister Shinzo Abe called for an emergency meeting of the UN Security Council.
He said Japan will not back down against any provocation and would maximise pressure on the North in its strong alliance with the US.
"We will not tolerate North Korea's reckless action," he told reporters.
The test is likely to trigger moves by the US and its allies to condemn North Korea's latest test as a violation of Security Council resolutions that prohibit its use of ballistic missile technology and possibly seek more sanctions.
Mr Trump has ramped up economic and diplomatic pressure on the North to prevent its development of a nuclear-tipped missile that could strike the US mainland.
Thus far, the pressure has failed to get North Korea's totalitarian government, which views a nuclear arsenal as key to its survival, to return to long-stalled international negotiations on its nuclear programme.
UN Security Council president Sebastiano Cardi said he was scheduled to brief the council on Wednesday.
Tuesday's launch came as the US discussed with South Korea next steps on North Korea.
The South's top nuclear negotiator, Lee Do-hoon, was in Washington for talks with Joseph Yun, the US envoy for North Korea policy.
The UN Security Council has scheduled an emergency meeting on North Korea's latest launch.
Italy chairs the council and its spokesman said the Wednesday afternoon meeting was requested by Japan, the US and South Korea.
The Security Council has already imposed its toughest-ever sanctions on Kim Jong Un's government in response to its escalating nuclear and ballistic missile programs and the US and Japan are likely to seek even stronger measures.