US house speaker Nancy Pelosi has left Malaysia ahead of an expected visit to Taiwan, escalating tensions with Beijing.

The plane carrying Ms Pelosi and her delegation left from a Malaysian air force base after a brief stopover that included a lunch meeting with Prime Minister Ismail Sabri Yaakob, an official said.

Ms Pelosi is on an Asian tour this week that is being closely watched to see if she will defy China’s warnings against visiting Taiwan. The government in Beijing claims the self-governing island as its own territory.

It is unclear where Ms Pelosi was heading from Malaysia, but local media in Taiwan reported that she would arrive on Tuesday night, becoming the highest-ranking elected US official to visit in more than 25 years.

The United Daily News, Liberty Times and China Times – Taiwan’s three largest national newspapers – cited unidentified sources as saying she would spend the night in Taiwan.

Taiwan’s foreign ministry declined to comment. Premier Su Tseng-chang did not explicitly confirm Ms Pelosi’s visit, but said on Tuesday that “any foreign guests and friendly lawmakers” are “very much welcome”.

China, which regards Taiwan as a renegade province to be annexed by force if necessary, has repeatedly warned of retaliation if Ms Pelosi visits, saying its military will “never sit idly by”.

“The US and Taiwan have colluded to make provocations first, and China has only been compelled to act out of self-defence,” Chinese foreign ministry spokesperson Hua Chunying told reporters in Beijing.

Ms Hua said China has been in constant communication with the US and made clear “how dangerous it would be if the visit actually happens”.

Any counter-measures China take will be “justified and necessary” in the face of Washington’s “unscrupulous behaviour”, she said.

China’s military threats have driven concerns of a new crisis in the Taiwan Strait, which separates the two sides, that could badly affect global markets and supply chains.

The White House on Monday decried Beijing’s rhetoric, saying the US has no interest in deepening tensions with China and “will not take the bait or engage in sabre-rattling”.

White House National Security Council spokesperson John Kirby underscored that the decision on whether to visit Taiwan was ultimately Ms Pelosi’s. He noted that members of US congress have routinely visited the island over the years.

US secretary of state Antony Blinken urged China to “act responsibly” if Ms Pelosi proceeds with the visit.

American officials have said the US military would increase its movement of forces and assets in the Indo-Pacific region if Pelosi visits Taiwan.

US Navy aircraft carrier USS Ronald Reagan and its strike group were in the Philippine Sea on Monday, according to officials.

Beijing sees official American contact with Taiwan as encouragement to make the island’s decades-old de facto independence permanent, a step US leaders say they do not support. Ms Pelosi, head of one of three branches of the US government, would be the highest-ranking elected American official to visit Taiwan since then-Speaker Newt Gingrich in 1997.

Ms Pelosi kicked off her Asian tour in Singapore on Monday as her possible visit to Taiwan sparked jitters in the region.

Singapore Prime Minister Lee Hsien Loong “highlighted the importance of stable US-China relations for regional peace and security” during talks with Pelosi, the city-state’s foreign ministry said.

This was echoed by Japanese foreign minister Yoshimasa Hayashi in Tokyo, who said stable ties between the two rival powers “are extremely important for the international community as well”.

China has been steadily ratcheting up diplomatic and military pressure on Taiwan. China cut off all contact with Taiwan’s government in 2016 after President Tsai Ing-wen refused to endorse its claim that the island and mainland together make up a single Chinese nation, with the Communist regime in Beijing being the sole legitimate government.

On Thursday, Ms Pelosi is to meet with South Korean National Assembly Speaker Kim Jin Pyo in Seoul for talks on security in the Indo-Pacific region, economic cooperation and the climate crisis, according to Mr Kim’s office. Ms Pelosi is also due to visit Japan, but it is unclear when she heading there.