Beijing (AFP) - China said Thursday it "firmly opposes" a meeting at the White House between US security officials and a senior Taiwanese politician, warning it could damage US-China relations.

Vice President-elect William Lai made the visit this week during a personal trip to the US, reported Taiwanese media outlet CNA.

On Monday, Lai had a 70-minute meeting with US National Security Council officials, according to CNA, without offering details on what was discussed.

The White House meeting has angered Beijing, which sees self-ruled Taiwan as part of its territory awaiting reunification, by force if necessary.

A Chinese foreign ministry spokeswoman said Thursday that China "firmly opposes" any official exchange between the US and Taiwan.

Washington "shall not arrange US leaders, government officials and Congress members to have any form of contact with Lai," said Hua Chunying at a regular press briefing.

She called for the US to "stop sending wrong signals to Taiwan independence forces to avoid causing serious harm to China-US relations."

The trip comes weeks after Lai was elected to office, along with Beijing-sceptic President Tsai Ing-wen who won a landslide second term.

Tsai does not acknowledge Beijing's view that Taiwan is part of "one China".

Taiwan and the United States do not have formal diplomatic ties, but Washington is Taipei's main weapons supplier.

Taiwan's foreign ministry declined to comment, saying the visit was a "private trip".

Lai was also expected to attend a high-profile National Prayer Breakfast in Washington on Thursday, Taiwan's United Daily News reported.

The event is traditionally attended by US presidents and President Donald Trump attended last year.