U.S. House Speaker Nancy Pelosi held talks with officials in Singapore on Monday at the start of her Asian tour, as questions swirled over a possible stop in Taiwan that has fueled tension with Beijing.

While there have been no official announcements, local media in Taiwan reported that Pelosi will arrive Tuesday night, becoming the highest-ranking elected U.S. 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 arrive in Taipei after visiting Malaysia and spend the night.

Such a visit will spark fury in Beijing, which regards Taiwan as its own territory and has repeatedly warned of “serious consequences” if the reported trip goes ahead.

“If Pelosi insists on visiting Taiwan, China will take resolute and strong measures to defend its sovereignty and territorial integrity,” Chinese Foreign Ministry spokesperson Zhao Lijian said in Beijing, without giving details.

“Those who play with fire will perish by it,” Zhao said. “We would like to once again admonish the U.S. that we are fully prepared for any eventuality and the PLA will never sit idly by.” The People’s Liberation Army is China’s military.

Chinese President Xi Jinping also warned the U.S. against meddling in Beijing’s dealings with the island in a phone call last week with President Joe Biden.

China has been steadily ratcheting up diplomatic and military pressure on Taiwan. Threats of retaliation for a visit by Pelosi have driven concerns of a new crisis in the Taiwan Strait, which separates the two sides, that could roil global markets and supply chains.

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

The Biden administration has tried to assure Beijing there was no reason to “come to blows” and that if such a visit occurred, it would signal no change in U.S. policy.

Taiwan and China split in 1949 after the Communists won a civil war on the mainland. Both sides say they are one country but disagree over which government is entitled to national leadership. They have no official relations but are linked by billions of dollars of trade and investment.

The United States switched diplomatic recognition from Taipei to Beijing in 1979, but maintains informal relations with the island. Washington is obligated by the Taiwan Relations Act, a federal law, to see that Taiwan has the means to defend itself.

Washington’s “One China policy” says it takes no position on the status of the two sides but wants their dispute resolved peacefully. Beijing promotes an alternative “One China principle” that says they are one country and the Communist Party is its leader.

John Kirby, a White House national security spokesman, told CNN that the U.S. “shouldn’t be intimidated” by China’s rhetoric or threats to retaliate if Pelosi visits Taiwan.

“We want to make sure that when she travels overseas, she can do so safely and securely,” Kirby told CNN on Monday. “There’s no reason for the Chinese rhetoric. There’s no reason for any actions to be taken. It is not uncommon for congressional leaders to travel to Taiwan, it is very much in keeping with our policy and is consistent with our support to Taiwan under the Taiwan Relations Act.”

A visit to Taiwan would be a career capstone for Pelosi, who increasingly uses her position in Congress as a U.S. emissary on the global stage. She has long challenged China on human rights and wanted to visit Taiwan earlier this year.

On Monday, Pelosi met with Singaporean Prime Minister Lee Hsien Loong, President Halimah Yacob and other Cabinet members.

Singapore’s Foreign Ministry said Lee welcomed a U.S. commitment to strong engagement with the region, and the two sides discussed ways to deepen U.S. economic involvement through initiatives such as the Indo-Pacific Economic Framework.

Lee and Pelosi also discussed the war in Ukraine, tensions surrounding Taiwan and mainland China, and climate change, it said in a statement. Lee “highlighted the importance of stable U.S.-China relations for regional peace and security,” it added, in an apparent allusion to reports of Pelosi’s visit to Taiwan.

Pelosi has said she is visiting Singapore, Malaysia, South Korea and Japan in a tour to discuss trade, the COVID-19 pandemic, climate change, security and “democratic governance.”

She is scheduled to be in Malaysia on Tuesday. A Parliament official, who was not authorized to speak to the media and declined to be identified by name, said Pelosi will call on Malaysian lower house speaker Azhar Azizan Harun. No further details were immediately available.

On Thursday, 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, Kim’s office said in a statement.

It declined to provide further details about her itinerary, including when she is arriving in South Korea and how long she’ll stay. Pelosi’s schedule for Wednesday remains unclear and there were no details on when she will head to Japan.

Pelosi’s delegation includes U.S. Reps. Gregory Meeks, chairman of the House Foreign Affairs Committee; Mark Takano, chairman of the House Committee on Veterans’ Affairs; Suzan DelBene, vice chair of the House Ways and Means Committee; Raja Krishnamoorthi, a member of the House Permanent Select Committee on Intelligence and chair of the Subcommittee on Economic and Consumer Policy of the House Committee on Oversight and Reform; and Andy Kim, a member of the House Armed Services and Foreign Affairs Committees.