US House Speaker Nancy Pelosi is believed to be headed to Taiwan on Tuesday in a visit that could significantly escalate tensions with Beijing, which claims the self-ruled island as its own territory. Pelosi is on an Asian tour this week that is being watched closely for whether she will defy warnings from China not to visit the island republic, a close US ally. China has vowed to retaliate if Pelosi becomes the highest-ranking elected US official to visit Taiwan in more than 25 years, but has not provided details. Speculation centered on threatening military exercises and possible incursions by Chinese planes and ships into areas under Taiwanese control. Chinese Foreign Minister Wang Yi said Washington’s betrayal “on the Taiwan issue is bankrupting its national credibility.” “Some American politicians are playing with fire on the Taiwan issue,” Wang said in a statement. “This will certainly not have a good result… the revelation of America’s intimidating face shows it once again as the world’s greatest saboteur of peace.” A plane carrying Pelosi and her delegation departed Malaysia on Tuesday after a brief stopover that included a working lunch with Prime Minister Ismail Sabri Yaakob. It was unclear where she was headed, although local media in Taiwan reported that Pelosi would arrive Tuesday night. The United Daily News, Liberty Times and China Times — Taiwan’s three largest national newspapers — cited unnamed sources who said he would spend the night in Taiwan. Taiwan’s foreign ministry declined to comment. Premier Su Cheng-Chang did not specifically confirm Pelosi’s visit, but said Tuesday that “any foreign guests and friendly lawmakers” are “very welcome.” Barricades were erected outside the Grand Hyatt hotel in Taipei where Pelosi was expected to stay amid heightened security. China, which views Taiwan as a renegade province that will be annexed by force if necessary, has repeatedly warned of retaliation if Pelosi visits, saying its military will “never stand idly by.” “The US and Taiwan have conspired to make provocations first, and China was forced to act only in self-defense,” Chinese Foreign Ministry spokeswoman Hua Chunying told reporters in Beijing on Tuesday. Hua said China is in constant communication with the US and made clear “how dangerous it would be if the visit actually takes place”. Any countermeasures taken by China would be “justified and necessary” in the face of Washington’s “ruthless behavior,” he said. Unknown hackers launched a cyber attack on the website of Taiwan’s Presidential Office, making it temporarily unavailable on Tuesday afternoon. The Presidential Office said the website was restored shortly after the attack, which overwhelmed traffic. “China believes that by launching a multi-pronged pressure campaign against Taiwan, the Taiwanese people will be intimidated. But they are wrong,” Wang Ting-yu, a lawmaker from the Democratic Progressive Party, said on Twitter in response to the attack. . China’s military threats have raised concerns of a new crisis in the 140km-wide Taiwan Strait that separates the two sides that could disrupt global markets and supply chains. The White House decried Beijing’s rhetoric on Monday, saying the US was not interested in deepening tensions with China and “will not take the bait or engage in rattling.” White House National Security Council spokesman John Kirby stressed that the decision whether to visit Taiwan was ultimately Pelosi’s. He noted that members of Congress have regularly visited the island over the years. Kirby said government officials are concerned that Beijing could use the visit as an excuse to take provocative retaliation, including military action, such as firing missiles into or around the Taiwan Strait, or encroachment on the island’s airspace and to conduct large-scale naval exercises in the strait. “Simply put, there is no reason for Beijing to turn a potential visit consistent with longstanding U.S. policy into some kind of crisis or use it as a pretext to increase aggressive military activity in or around the Taiwan Strait.” , Kirby said. US Secretary of State Anthony Blinken also urged China to “act responsibly” if Pelosi goes ahead with the visit. “If the speaker decides to visit and China tries to create some kind of crisis or otherwise escalate tensions, that will be all about Beijing,” he told reporters at UN headquarters in New York. “We are looking for them, should he decide to visit, to act responsibly and not engage in any escalation in the future.” US officials said the US military would increase the movement of forces and resources to the Indo-Pacific region if Pelosi visits Taiwan. The aircraft carrier USS Ronald Reagan and its strike group were in the Philippine Sea on Monday, according to officials who spoke on condition of anonymity to discuss military operations. The Reagan, the cruiser USS Antietam and the destroyer USS Higgins left Singapore after a port visit and moved north to their home port in Japan. The aircraft carrier carries an array of aircraft, including F/A-18 fighter jets and helicopters, as well as sophisticated radar systems and other weapons. Taiwan and China split in 1949 after the Communists won a civil war on the mainland. The US maintains informal relations and defense ties with Taiwan, even though it recognizes Beijing as the government of China. Beijing sees formal US contact with Taiwan as an encouragement to make permanent the island’s decades-long de facto independence, a step US leaders say they do not support. Pelosi, head of one of the three branches of the US government, would be the highest-ranking elected US official to visit Taiwan since then-Speaker Newt Gingrich in 1997. Flight-tracking website Flightradar24 reported that Pelosi’s plane, a US Air Force Boeing C-40C, was the most watched in the world on Tuesday afternoon with 300,000 viewers. Pelosi used her position in the US Congress as the US envoy on the world stage. He has long challenged China on human rights, including in 2009 when he delivered a letter to then-President Hu Jintao calling for the release of political prisoners. She had attempted to visit the island republic of Taiwan earlier this year before testing positive for COVID-19. Pelosi kicked off her Asian tour in Singapore on Monday as her potential visit to Taiwan sparked concern in the region. Singapore Prime Minister Lee Hsien Loong “stressed the importance of stable US-China relations for regional peace and security” during talks with Pelosi, the city-state’s foreign ministry said. That was echoed by Japanese Foreign Minister Yoshimasa Hayashi in Tokyo, who said strong ties between the two rival powers “are extremely important to the international community as well.” The Philippines urged the US and China to be “responsible actors” in the region. “It is important for the US and China to ensure continuous communication to avoid any miscalculation and further escalation of tensions,” said Foreign Affairs spokeswoman Teresita Daza. China is steadily increasing diplomatic and military pressure on Taiwan. China severed all contact with Taiwan’s government in 2016 after President Tsai Ing-wen refused to support her claim that the island and mainland together form a single Chinese nation, with the communist regime in Beijing the only legitimate government. On Thursday, Pelosi will 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 Kim’s office. Pelosi is also scheduled to visit Japan, but it is unclear when she will go there. —— Ng reported from Kuala Lumpur, Malaysia. Associated Press reporters Jim Gomez in Manila, Philippines, and Mari Yamaguchi in Tokyo contributed to this report