The Speaker of the US House of Representatives, Nancy Pelosi, is beginning a tour of Singapore, Malaysia, South Korea and Japan, her office says – with no mention of a possible visit to Taiwan.
There has been intense speculation that she may visit the self-ruled island.
Taiwan is claimed by China – which has warned of “serious consequences” if she goes there.
No high-ranking US elected official has visited Taiwan in 25 years.
Ms Pelosi, a California Democrat, tweeted that the six-person Congressional delegation tour would seek to “reaffirm America’s unshakeable commitment to our allies and friends in the region”.
Her office said the tour was to the “Indo-Pacific region” – “including” visits to Singapore, Malaysia, South Korea and Japan.
China sees Taiwan as a breakaway province that must become a part of the country. Beijing has not ruled out the possible use of force to achieve this in the future.
Chinese officials have expressed anger over what they view as growing diplomatic engagement between Taipei and Washington. There was a surprise visit to the island by six US lawmakers in April.
The US has formal diplomatic ties with China, and not Taiwan.
Ms Pelosi has long been a vocal critic of the Chinese leadership, denouncing its human rights record. She has met pro-democracy dissidents and visited Tiananmen Square to commemorate victims of the 1989 massacre.
- Nancy Pelosi’s long history of opposing Beijing
Her original plan was to visit Taiwan in April, but she postponed the trip after she tested positive for Covid-19.
Earlier this month she said it was “important for us to show support for Taiwan”.
President Joe Biden has said the US military believes a Pelosi visit to Taiwan is “not a good idea right now”.
The statement from her office on Sunday said the tour would “focus on mutual security, economic partnership and democratic governance in the Indo-Pacific region”.
Their talks will also cover trade, the climate crisis and human rights.
The delegates accompanying Ms Pelosi are leading members of the House of Representatives: Gregory Meeks, Mark Takano, Suzan DelBene, Raja Krishnamoorthi and Andy Kim.
The last House Speaker to visit Taiwan was Republican Newt Gingrich, in 1997.
California wildfire: McKinney Fire spreads rapidly in north of state
Hundreds of firefighters in California are battling the largest wildfire to spread in the state so far this year.
The McKinney Fire, which started in the northern Siskiyou county on Friday, has already burnt 21,000 hectares (52,500 acres), the state’s fire service said.
At least 2,000 residents as well as trekkers on the Pacific Crest hiking trail have left the area, authorities say. Homes have been destroyed.
It was 0% contained as of Sunday, the emergency service’s latest report said.
A red flag warning indicating the threat of dangerous fire conditions is in place, as California suffers from persistent drought conditions.
A state of emergency was declared in Siskiyou county on Saturday, after homes were destroyed and infrastructure was threatened, state governor Gavin Newsom said.
The fire was “intensified and spread by dry fuels, extreme drought conditions, high temperatures, winds and lightning storms”, he added.
Authorities warn that possible thunderstorms could result in more fires developing in the coming days.
The US Forest Service warned that conditions could be “extremely dangerous for firefighters, as winds can be erratic, and extremely strong, causing the fire to spread in any direction”.
Meteorologist Brad Schaaf told the New York Times, however, that smoke from the McKinney blaze could lower temperatures, which would then counteract some of the dangerous “thunderstorm ingredients”.
The fire is the second major blaze to hit the state in recent days. The Oak Fire, near Yosemite National Park, is still roaring after eight days but has been 67% contained, the fire department Cal Fire said.
California, which is facing serious drought conditions, still has months of its fire season ahead.
Climate change increases the risk of the hot, dry weather that is likely to fuel wildfires.
The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.