US President Donald Trump said the United States is ready to solve the North Korean "problem" without China if necessary.
"North Korea is looking for trouble," Trump wrote on Twitter on Tuesday. "If China decides to help, that would be great. If not, we will solve the problem without them! U.S.A."
The warning from Trump comes as Russia admitted it held concerns that the US would attack after North Korea warned it had US bases in nuclear sights.
Trump launched a missile strike on Syria late Thursday while meeting with Chinese leader Xi Jinping at his Mar-a-Lago resort in Florida.
The move was widely interpreted as a warning to North Korea as well as retaliation for the Damascus regime's suspected sarin attack against civilians in a rebel-held town in Syria.
"I explained to the President of China that a trade deal with the US will be far better for them if they solve the North Korean problem!" Trump wrote in an earlier tweet.
The United States has deployed a naval strike group - which includes the Nimitz-class aircraft carrier USS Carl Vinson - to the Korean peninsula in a show of force.
Trump has previously threatened unilateral action against Pyongyang if China, the North's sole major ally, fails to help curb its neighbour's nuclear ambitions.
Turnbull urges China to step in as tensions heat up
Prime Minister Malcolm Turnbull has again urged China to exercise its "undoubted influence" over the North Korean regime, to urge it to pull back as tensions in the area heat up.
America has sent an aircraft carrier loaded with fighter jets towards the hermit nation, and the North Koreans have responded by warning they're ready for war.
"The reckless and dangerous conduct of the North Korean regime is threatening peace and stability not just in the region but the whole world," Mr Turnbull told reporters in New Delhi on Tuesday.
"We continue to call on China to exercise the undoubted influence it has over the North Korean regime to pull it back from further reckless conduct."
He discussed a wide range of regional security issues with Indian prime minister Narendra Modi when they met on Monday.
Australia and other UN countries continue to apply sanctions to North Korea.
Snooker champ tells Trump to 'chill bruv'
Five-time world snooker champion Ronnie O'Sullivan urged Trump to "chill bruv" in response to a tweet about North Korea.
'The Rocket' weighed in with his opinions on the matter in a series of tweets.
"China don't need the USA.. you need China more than they need you," he advised the president.
"I wouldn't do business with the USA all you do is have wars.
"Donald you need to chill bruv. Let's not have another Iraq.. let people run there [sic] own country. USA ain't got it great.. pure debt."
O'Sullivan added that "people can change the world".
Russia fears US might attack North Korea
Russia said it hoped forthcoming talks in Moscow with US Secretary of State Rex Tillerson would be productive, but said it was extremely worried the United States might decide to unilaterally attack North Korea.
North Korea is emerging as one of the most pressing foreign policy problems for US President Donald Trump.
Pyongyang has conducted five nuclear tests and is working to develop nuclear-tipped missiles that can reach the United States.
A US official told Reuters over the weekend that a US Navy strike group led by a nuclear-powered aircraft carrier was steaming towards the western Pacific as a show of force.
The Russian foreign ministry, in a statement ahead of his visit, said it was concerned about many aspects of US foreign policy, including on Libya, Yemen and Syria, but said it was particularly concerned about North Korea.
"We are really worried about what Washington has in mind for North Korea after it hinted at the possibility of a unilateral military scenario," the statement said.
"It's important to understand how that would tally with collective obligations on de-nuclearising the Korean peninsula, something that is underpinned in U.N. Security Council resolutions."