China confirms it tracked US ships and urges United States to stop its ‘provocative actions’ in the disputed waters.

Navy warships have sailed near islands claimed by China in the disputed South China Sea twice in the past few days, the United States military told Reuters on Thursday, at a time of tension between the world’s two-largest economies.

The busy waterway is one of a number of flashpoints in the US-China relationship, which include a trade war, US sanctions, Hong Kong and Taiwan.

Earlier this week during high-level talks, China called on the US military to stop flexing its muscles in the South China Sea and adding “new uncertainties” over democratic Taiwan, which is seen as a wayward province and claimed by China.

The US Navy regularly vexes China by conducting what it calls “Freedom of Navigation Operations” by ships close to some of the islands China occupies, asserting freedom of access to international waterways.

On Wednesday, the littoral combat ship Gabrielle Giffords travelled within 12 nautical miles (22.2 kilometres) of Mischief Reef, Commander Reann Mommsen, a spokeswoman for the US Navy’s Seventh Fleet, told Reuters.

On Thursday, the destroyer Wayne E Meyer challenged restrictions on innocent passage in the Paracel Islands, Mommsen said.

“These missions are based in the rule of law and demonstrate our commitment to upholding the rights, freedoms, and lawful uses of the sea and airspace guaranteed to all nations,” she added.

‘Indisputable sovereignty’

China’s military confirmed on Friday that the two US warships had sailed through the contentious waterway and said it had tracked the passage of the American ships.

“We urge (the United States) to stop these provocative actions to avoid any unforeseeable accidents,” the spokesman for China’s Southern Theatre Command said in a statement.

“China has indisputable sovereignty over the South China Sea islands and its surrounding area.”

China claims almost the entire South China Sea, where it has built artificial islands and established military outposts.

Brunei, Malaysia, the Philippines, Taiwan and Vietnam also claim parts of the sea.

The US accuses China of militarising the South China Sea and trying to intimidate Asian neighbours who might want to exploit its extensive oil and gas reserves.

US Defense Secretary Mark Esper met Chinese Defence Minister Wei Fenghe earlier this week for closed-door talks on the sidelines of a gathering of defence ministers in Bangkok.

Wei urged Esper to “stop flexing muscles in the South China Sea and to not provoke and escalate tensions in the South China Sea,” a Chinese spokesman said.

Esper has accused Beijing of “increasingly resorting to coercion and intimidation to advance its strategic objectives” in the region.