US Secretary of State Rex Tillerson has arrived in China for the final leg of his East Asia tour, which has been dominated by anxieties over North Korea.
On Friday, Mr Tillerson warned Pyongyang that a military response would be on the table if it threatened South Korea or US forces.
President Donald Trump tweeted that North Korea was “behaving very badly”.
He added that China – Pyongyang’s main ally – had done “little to help”.
Beijing is likely to express its anger at being told to rein in nuclear-armed North Korea during Mr Tillerson’s visit.
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It will also voice its opposition to a new US missile defence system installed in South Korea earlier this month.
Collision course: By Carrie Gracie, BBC China editor
Recent North Korean missile tests have only raised the stakes for Mr Tillerson’s talks in Beijing.
President Trump tweeted again yesterday that China was not doing enough to help.
But the Chinese government insists it already observes UN sanctions against Pyongyang and bristles at the deployment of a new American anti-missile system in South Korea.
Beijing says all players on the Korean peninsula are like accelerating trains on a collision course. It warns that the only way to make North Korea disarm is through dialogue….which is something the US secretary of state has already ruled out.
As the first senior Trump administration official to visit China, Mr Tillerson will also discuss plans for a possible presidential summit next month. The timing is hardly auspicious.
The US says the Terminal High-Altitude Area Defense system (Thaad) is designed to protect against threats from North Korea.
But China has claimed the system goes “far beyond” the defence needs of the Korean peninsula.
Mr Tillerson, a former oil executive with no prior diplomatic experience, is scheduled to meet China’s two most senior diplomats on Saturday. On Sunday, he will meet Chinese President Xi Jinping.
Mr Xi is scheduled to visit the United States next month for his first meeting with President Trump.
Some commentators expect Mr Tillerson to downplay any tensions between the two countries ahead of that encounter.
However, a US official told Reuters that Mr Tillerson may raise the prospect of imposing “secondary sanctions” on Chinese banks and other firms that do business with North Korea in defiance of sanctions.
North Korea launched four ballistic missiles last week, and is working to develop nuclear-tipped missiles that can reach the US.
Rex Tillerson arrives for tricky first China visit}