The USS Green Bay, an amphibious dock landing ship, was to stop in Hong Kong on Saturday, while the guided missile cruiser USS Lake Erie planned a port call there next month, Commander Nate Christensen, deputy spokesman for the United States Pacific Fleet, said in a statement.

"The Chinese government denied requests for port visits to Hong Kong" by the two vessels, Christensen said.

He referred the question of why the request was denied to China.

Weeks of protests in the semi-autonomous former British colony of Hong Kong have escalated, with protesters blocking and paralyzing the city's airport for a second day on Tuesday.

Beijing has increasingly pitched the anti-government protests as funded by the West, but has provided little evidence.

Early this month, Beijing demanded that US diplomats based in Hong Kong "stop interfering" in the city's affairs, after reports that they met with pro-democracy activists.

US President Donald Trump, however, faced criticism at home on Tuesday for avoiding harsh words over Beijing's response to the protesters, who object to sliding freedoms in the semi-autonomous global financial center.

A US Navy ship last visited Hong Kong in April.

Last September, with US-China trade tensions soaring, Beijing did not approve a request for the USS Wasp, an amphibious assault ship, to visit.