The US and China are working on a “range of options” on North Korea, the US top security adviser has said, as tensions mount over the country’s nuclear and missile programmes.
Lt Gen HR McMaster told ABC News there was consensus with China that this was a “situation that just can’t continue”.
The comments come after a failed missile test launch by North Korea and a massive military parade.
President Trump had earlier said China was “working with us” on the issue.
Beijing, Pyongyang’s biggest ally, has come under pressure from Washington to exert more pressure on its neighbour.
Sunday’s comments appear to be the first confirmation that both countries are working together on how to deal with the North Korean issue.
Gen McMaster, who was in the Afghan capital, Kabul, said the US would respond “in the best interest of the American people”.
“The president has made clear that he will not accept the United States and its allies and partners in the region being under threat from this hostile regime with nuclear weapons,” he said.
“I think there’s an international consensus now, including the Chinese and the Chinese leadership, that this is a situation that just can’t continue.”
President Donald Trump last week met Chinese President Xi Jinping, who offered co-operation on “communication and co-ordination”, the BBC’s Robin Brant in Shanghai reports.
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Earlier on Sunday, South Korean and US military officials said a North Korean missile had detonated soon after launch. The US Pacific Command said it believed it to be a ballistic missile.
One unnamed US official said it was unlikely to have been an intercontinental (ICBM) missile, but investigations were continuing.
Ballistic missiles follow high trajectories and are initially powered and guided, but fall to their target under gravity. ICBMs follow a sub-orbital trajectory, others stay within the atmosphere.
North Korea is banned from any missile or nuclear tests by the UN, though it has repeatedly broken those sanctions.
UK Foreign Secretary Boris Johnson issued another warning to North Korea after its failed missile launch.
“They must stop these belligerent acts and comply with UN resolutions,” he said.