North Korea test-fired a ballistic missile on Saturday shortly after US Secretary of State Rex Tillerson warned that failure to curb its nuclear and ballistic missile programs could lead to "catastrophic consequences".
US and South Korean officials said the test, from an area north of the North Korean capital, Pyongyang, appeared to have failed, in what would be North Korea's fourth successive unsuccessful missile test since March.
The test came as the USS Carl Vinson aircraft carrier group arrived in waters near the Korean peninsula, where it will join the USS Michigan, a guided missile submarine that docked in South Korea on Tuesday.
Tillerson, in a UN Security Council meeting on North Korea, repeated the Trump administration's position that all options were on the table if Pyongyang persisted with its nuclear and missile development.
"The threat of a nuclear attack on Seoul, or Tokyo, is real, and it's only a matter of time before North Korea develops the capability to strike the US mainland," Tillerson said.
"Failing to act now on the most pressing security issue in the world may bring catastrophic consequences," he said.
US President Donald Trump, who told Reuters in an interview on Thursday North Korea was his biggest global challenge, said the launch was an affront to China, the North's sole main ally.
"North Korea disrespected the wishes of China & its highly respected President when it launched, though unsuccessfully, a missile today. Bad!," Trump said in a post on Twitter after the launch.
Chinese Foreign Minister Wang Yi told the UN meeting on Friday it was not only up to China to solve the North Korean problem.
"The key to solving the nuclear issue on the peninsula does not lie in the hands of the Chinese side," Wang said.
Both China and Russia rebuked a US threat of military force.
US officials, speaking on condition of anonymity, said the North Koreans had probably tested a medium-range missile known as a KN-17 and it appeared to have broken up within minutes of taking off.
The South Korean military said the missile, fired from the Pukchang region in a northeasterly direction, reached an altitude of 71 km (44 miles) before disintegrating a few minutes into flight. It said the launch was a clear violation of UN resolutions and warned the North not to act rashly.
The North has been conducting missile and nuclear weapons related activities at an unprecedented rate since the beginning of the year and is believed to have made some progress in developing intermediate-range and submarine-launched missiles.
The United States has been hoping North Korea's sole major ally, China, can bring pressure to bear. But China says the United States must not over-estimate the influence it has over its neighbor.
There was no immediate reaction to the launch from China.
Trump, in his interview with Reuters, said he had praised Chinese leader Xi Jinping for "trying very hard" on North Korea, though Trump warned a "major, major conflict" between the United States and North Korea was possible.
Tension on the Korean peninsula has been high for weeks over fears the North may conduct a long-range missile test, or its sixth nuclear test, around the time of the April 15 anniversary of its state founder's birth, or the day marking the founding of its military.
With North Korea acting in defiance of the pressure, the United States could conduct new naval drills and deploy more ships and aircraft in the region, a U.S. official told Reuters.
Japan condemned the launch as unacceptable and authorities stopped some train services in Japan as a precaution, in case the missile had been fired at Japan, a transit system spokesman said.
A Japanese military official said its navy on Saturday completed an exercise with the Carl Vinson in the channel separating the Korean peninsula from Japan, meaning the U.S. carrier had arrived in the Sea of Japan.
Kim Dong-yub, an expert at Kyungnam University's Institute of Far Eastern Studies in Seoul, said North Korea might have got the data it wanted with the missile's short flight, then blown it up in a bid to limit the anger of China, which disapproves of the North's weapons programs and has warned it against further provocation.
North Korea rattled world powers in February when it successfully launched a new intermediate-range ballistic missile that it said could carry a nuclear weapon. It also successfully tested ballistic missiles on March 6.
It is not clear what has caused the series of failed missile tests since then.
The Trump administration could respond to the test by speeding up its plans for new US sanctions, including possible measures against specific North Korean and Chinese entities, said the US official, who declined to be identified.
"Something that's ready to go could be taken from the larger package and expedited," said the official.
The UN Security Council is likely to start discussing a statement to condemn the missile launch, said diplomats. The Security Council traditionally condemns all missile launches by Pyongyang.
But condemnations and sanctions resolutions since 2006, when North Korea conducted its first nuclear test, have done little to impede its push for ballistic missiles and nuclear arms.
The South Korean politician expected to win a May 9 presidential election, Moon Jae-in, who has advocated a more moderate policy on the North, called the test an "exercise in futility".
"We urge again the Kim Jong Un regime to immediately stop reckless provocative acts and choose the path to cooperate with the international community," Park Kwang-on, a spokesman for Moon, said in a statement, referring to the North Korean leader.
Moon has been critical of the deployment of an advanced US missile defense system in the South intended to counter North Korea's missile threat, which China also strongly objects to.
Report by By Jack Kim and Ju-min Park (Seoul); Additional reporting by Soyoung Kim (Seoul), Idrees Ali, David Brunnstrom and Matt Spetalnick (Washington), Tim Kelly (Tokyo) and Michelle Nichols and Lesley Wroughton at the United Nations; Editing Lincoln Feast, Robert Birsel; Reuters