North Korea test-fired a ballistic missile on Saturday, the South Korean and US militaries said, defying warnings from the United States and the reclusive state's main ally, China, which have tried for years to rein in its arms programmes.
The test, from an area north of the North Korean capital, Pyongyang, appeared to have failed, US and South Korean officials said, in what would be North Korea's fourth successive unsuccessful missile test since March.
The test came as US Secretary of State Rex Tillerson warned the UN Security Council that failure to curb North Korea's nuclear and ballistic missile programmes could lead to "catastrophic consequences".
U.S. officials, speaking on condition of anonymity, said the missile was probably a medium-range weapon known as a KN-17 and appears to have broken up within minutes of taking off.
South Korea said the North was playing with fire and warned it of tougher U.N. sanctions.
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 U.N. 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.
U.S. 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.
"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.
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 neighbour.
Just before the missile test, Chinese Foreign Minister Wang Yi told the U.N. Security Council on meeting on North Korea 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 U.S. threat of military force.
There was no immediate reaction to the launch from China. Japan condemned it as unacceptable.
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 this week.
In a show of force, the United States is sending the USS Carl Vinson aircraft carrier group to waters off the Korean peninsula, where it will join the USS Michigan, a nuclear submarine that docked in South Korea on Tuesday.
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.
The timing of the launch suggested a complex North Korean message to the world, said Kim Dong-yub, an expert at Kyungnam University's Institute of Far Eastern Studies in Seoul.
"It was planned at a complicated timing around the end of the South Korea-U.S. joint military drills, the United States talking about military options and the announcement of North Korea policies and the Security Council meeting," Kim said.
South Korean and U.S. forces have been conducting annual military drills since the beginning of March that conclude at the end of April.
Kim 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 programmes 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 U.S. sanctions, including possible measures against specific North Korean and Chinese entities, said the U.S. 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 U.N. Security Council is likely to start discussing a statement to condemn the missile launch, said diplomats, adding that it was unlikely to be issued on Friday. The Security Council traditionally condemns all missile launches by Pyongyang.
"It could have happened today exactly because we had the meeting," Italian U.N. Ambassador Sebastiano Cardi, chair of the Security Council's North Korean sanctions committee, told reporters.
"It's illegal, it should not be done, it's another provocative action by North Korea."
But such routine condemnation and a series of 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 including giving up its nuclear programme," 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 U.S. missile defense system in the South intended to counter North Korea's missile threat, which China also strongly objects to.