The Kremlin warned the United States on Tuesday that an expected visit to Taiwan by U.S. House Speaker Nancy Pelosi would put it on a collision course with China and provoke tensions in the region.

"We cannot say for sure right now whether she will or will not get there, but everything about this tour and the possible visit to Taiwan is purely provocative," Kremlin spokesperson Dmitry Peskov told reporters.

China has repeatedly warned Pelosi against going to Taiwan, which it claims as its own. Beijing says a Pelosi visit would contravene the "one China" principle that Washington has vowed to abide by.

Pelosi left Malaysia and was expected to visit Taiwan, escalating tensions with Beijing, which claims the self-ruled island as its own territory.

The plane carrying 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 on condition of anonymity because he wasn't authorized to release details to the media.

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.

It was unclear where she was headed from Malaysia, but local media in Taiwan reported that she would arrive on 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 spend the night in Taiwan.

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

Chinese Foreign Minister Wang Yi said Tuesday that U.S. politicians who "play with fire" on the Taiwan issue will "come to no good end," according to a ministry statement.

He did not specify which politicians.

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

Taiwan prepares shelters

Taiwan is preparing its air-raid shelters as rising tension with China and Russia's invasion of Ukraine raise new fears about the possibility of a Chinese attack on the democratic island.

China considers Taiwan its territory and has increased military activity in the air and seas around it. Taiwan vows to defend itself and has made strengthening its defenses a priority, with regular military and civil defense drills.

The preparations include designating shelters where people can take cover if Chinese missiles start flying in, not in purpose-built bunkers but in underground spaces like basement car parks, the subway system and subterranean shopping centers.

The capital of Taipei has more than 4,600 such shelters that can accommodate some 12 million people, more than four times its population.

Shelter entrances are marked with a yellow label, about the size of an A4 piece of paper, with the maximum number of people it can take.

A senior official in the city office in charge of the shelters said events in Europe had brought a renewed sense of urgency.

"Look at the war in Ukraine," Abercrombie Yang, a director of the Building Administration Office, told Reuters.

"There's no guarantee that the innocent public won't get hit," he said, adding that that was why the public had to be informed.

The White House on Monday decried Beijing's rhetoric, saying the U.S. has no interest in deepening tensions with China and "will not take the bait or engage in saber rattling."

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

Kirby said administration officials are concerned that Beijing could use the visit as an excuse to take provocative retaliatory steps, including military action such as firing missiles in the Taiwan Strait or around Taiwan, or flying sorties into the island’s airspace and carrying out large-scale naval exercises in the strait.

U.S. Secretary of State Antony Blinken also urged China to "act responsibly" if Pelosi proceeds with the visit.

"If the speaker does decide to visit, and China tries to create some kind of a crisis or otherwise escalate tensions, that would be entirely on Beijing," he told reporters at U.N. headquarters in New York. "We are looking for them, in the event she decides to visit, to act responsibly and not to engage in any escalation going forward."

U.S. officials have said the U.S. military would increase its movement of forces and assets in the Indo-Pacific region if Pelosi visits Taiwan. U.S. Navy 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 homeport in Japan. The carrier has an array of aircraft onboard, 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 U.S. maintains informal relations and defense ties with Taiwan even as it recognizes Beijing as the government of China.

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.

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 U.S.-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."

The Philippines urged the U.S. and China to be "responsible actors" in the region. "It is important for the U.S. and China to ensure continuing communication to avoid any miscalculation and further escalation of tensions," said Ministry of Foreign Affairs spokesperson Teresita Daza.

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.