China warned that a "storm is about to break” on the Korean peninsula as the US moved warships to the area and Pyongyang stepped up a threat to defend itself with nuclear weapons in the face of pressure from President Donald Trump.
Speaking a week after Mr Trump held a summit with China’s President Xi Jinping when the two leaders held discussions about North Korea, Wang Yi, the Chinese foreign minister, said the situation was on a "knife edge”.
Cautioning of the risk of a breaking storm, he urged all parties to "refrain from provoking and threatening each other . . . and not let the situation get to an irreversible and unmanageable stage.”
North Korea will celebrate the 105th birthday of Kim Il Sung, its late founding leader, on Saturday and Washington and Beijing worry the nation will mark the occasion with a provocation, such as a missile or nuclear test.
Tension has risen dramatically as Mr Trump has hardened the US stance on Pyongyang. He wants China to pressure North Korea into abandoning its nuclear programme. But he has also made it clear — first in an interview with the Financial Times — that he is prepared to take unilateral action.
The US believes North Korea is moving closer to being able to hit America with a nuclear-armed missile. Mr Trump has insisted that he will not allow Pyongyang to achieve the capability to launch a nuclear strike against the US mainland, while the renegade state has repeatedly insisted it will do just that if American forces ever attack.
North Korea on Friday accused Mr Trump of creating a "vicious cycle” of tension. Han Song Ryol, the country’s vice-minister of foreign affairs, warned Washington that Pyongyang would not hesitate to use its nuclear weapons as a deterrent.
"We’ve got a powerful nuclear deterrent already in our hands, and we certainly will not keep our arms crossed in the face of a US pre-emptive strike,” Mr Han told the Associated Press.
The Pentagon has deployed the USS Carl Vinson strike group, which includes an aircraft carrier and guided-missile destroyers, to the area. One US official said there were two Aegis ships nearby — part of a constellation of military assets that could be used to shoot down a North Korean missile.
A US media report saying Washington was prepared to launch a pre-emptive strike to prevent another North Korean nuclear test sparked alarm on the Korean peninsula on Friday, although US officials downplayed it as scaremongering.
North Korea has already tested five nuclear devices, including two last year, and experts believe another test is imminent.
Bonnie Glaser, a China expert at CSIS, a think-tank, said there were some signs of more Chinese pressure.
She pointed out that China had turned back North Korean ships carrying coal exports in line with UN sanctions, and noted tough statements in China’s semi-official media about public support for halting oil exports if the regime "makes another provocative move this month”.
"Trump is giving the Chinese an opportunity to step up pressure on their own,” Ms Glaser said. "If they don’t, the US is going to pursue secondary sanctions on Chinese entities.”
South Korea, which as a US ally would be vulnerable to retaliation if conflict broke out between Pyongyang and Washington, played down the likelihood of military action.
The country is facing a power vacuum after the impeachment of former president Park Geun-hye. Presidential elections are scheduled for May 9, but a top contender has already slammed the US for excluding South Korea from deliberations.
"I want to say it sternly. Military action on the Korean peninsula cannot happen without Korea’s consent,” said Moon Jae-in, leader of the opposition Democratic party.
Experts expect any military strike against North Korea’s weapons facilities to trigger retaliation against the South. Seoul, which has a population of 20m people and lies 50km from the demilitarised zone dividing the two countries, would probably bear the brunt of such attacks.