China's President Xi Jinping has called for a "peaceful" resolution to tensions over North Korea, in a phone conversation with US President Donald Trump, Chinese state media said.
On Tuesday Mr Trump tweeted that the US was not afraid of acting alone on North Korea if China would not help.
Tensions have risen on the Korean peninsula after the dispatch of US warships to the region.
North Korea reacted with anger, saying it would defend itself "powerfully".
Mr Xi and Mr Trump had met in person just last weekend at a summit in Florida where they discussed North Korea.
Their phone call took place on Wednesday morning, according to Chinese state broadcaster CCTV. The White House has not released any details.
During the conversation, Mr Xi said China "is committed to the target of denuclearisation on the peninsula, safeguarding peace and stability on the peninsula, and advocates resolving problems through peaceful means," CCTV said.
Earlier on Wednesday, editorials published by Chinese state media outlet Global Times called on North Korea to "hit the brakes for peace", noting that the US "doesn't plan to co-exist with a nuclear-armed Pyongyang.
"Pyongyang can continue its tough stance, however, for its own security, it should at least halt provocative nuclear and missile activities. Pyongyang should avoid making mistakes at this time."
'North Korea is looking for trouble'
The call came hours after Mr Trump tweeted on Tuesday about his earlier meeting with Mr Xi.
"I explained to the President of China that a trade deal with the U.S. will be far better for them if they solve the North Korean problem!" he said.
"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."
In a Tuesday interview with US news channel Fox Business Network, Mr Trump also said: "We are sending an armada. Very powerful... We have submarines. Very powerful. Far more powerful than the aircraft carrier."
Earlier this week the Carl Vinson Strike Group, which comprises an aircraft carrier and other warships, was diverted from Singapore to the west Pacific, where it recently conducted exercises with South Korea's navy.
The Japanese navy has also planned military exercises with the US warships, the Reuters wire agency reported.
The ships' deployment angered North Korea, which said it proved Pyongyang was right to develop nuclear weapons to defend itself or use in a pre-emptive strike.
It added that the US showed "reckless moves for invading", and warned it would defend itself "by powerful force of arms".
North Korea has carrying out missile tests with increasing frequency in recent months, despite a ban on its nuclear and missile activity by the UN.
It claimed earlier this year that it was close to testing an inter-continental ballistic missile (ICBM) carrying a nuclear warhead - which could possibly reach North America - although experts have cast serious doubts on such claims.