Japanese warships will join a US navy strike group heading towards North Korean waters, as China attempted to ease mounting tensions over Pyongyang’s nuclear ambitions.
The act of solidarity with Donald Trump’s "armada" follows the US president's warning that the US would act alone against North Korea if Beijing failed to rein in its wayward ally.
Xi Jinping, the Chinese president, responded by urging a “peaceful resolution to tensions” in a telephone conversation with Mr Trump.
The call came as an influential state-run Chinese newspaper warned that the Korean peninsula was the closest it has been to a "military clash" since North Korea's first nuclear test in 2006.
Tensions are escalating sharply over fears that North Korea may carry out another nuclear test on Saturday, in defiance of China and the US. The date marks the 105th anniversary of the birth of Kim Il-sung, the founder of the nation.
The North has carried out five nuclear tests since 2006, two of them last year.
Washington has sent a navy strike group led by aircraft carrier USS Carl Vinson to the region, a force which was described by Mr Trump as an “armada”.
The US president also told Fox Business Network that submarines were being sent which were “far more powerful than the aircraft carrier.”
Mr Trump sent a tweet on Tuesday which warned that the US would “solve the problem” unilaterally if China was not willing to help.
Chinese media said President Xi told Mr Trump in yesterday's call that China would maintain “communication and co-ordination” with Washington over the North Korean issue.
“President Xi made it clear that China wants a Korean Peninsula free of nuclear weapons, as well as a peaceful resolution to tensions,” Chinese state broadcaster CCTV said in its report of the call.
North Korean media responded to Mr Trump’s threat by warning of a nuclear strike. The official Rodong Sinmun newspaper said: "Our revolutionary strong army is keenly watching every move by enemy elements with our nuclear sight focused on the US invasionary bases not only in South Korea and the Pacific operation theatre but also in the US mainland.”
North Korea is looking for trouble. If China decides to help, that would be great. If not, we will solve the problem without them! U.S.A.— Donald J. Trump (@realDonaldTrump) April 11, 2017
White House spokesman Sean Spicer said that Pyongyang had been put "clearly on notice" by Mr Trump but he dismissed the North’s nuclear threat.
"I think there is no evidence that North Korea has that capability at this time," he said.
But Japan, alarmed at Pyongyang’s military buildup, is planning to conduct exercises with the Vinson strike carrier group in waters close to its territory, Reuters and several Japanese outlets reported yesterday.
Meanwhile, China’s Global Times newspaper said that Mr Trump’s threat to act had become more credible following cruise missile strikes carried out by Washington against a Syrian air base which the Pentagon said was used to store chemical weapons.
The possibility of conflict over North Korea is more likely now than it has been for over a decade, the nationalist tabloid said, as it pointed to US “arrogance” following Mr Trump’s air strikes on Syria.
“The Korean Peninsula has never been so close to a military clash since the North conducted its first nuclear test in 2006,” said the newspaper, which has close links to China’s ruling Communist Party.
“If Pyongyang conducts its sixth nuclear test in the near future, the possibility of US military action against it will be higher than ever.
“Not only (is) Washington brimming with confidence and arrogance following the missile attacks on Syria, but Trump is also willing to be regarded as a man who honours his promises.”