Taipei, Taiwan - House Speaker Nancy Pelosi has arrived in Taiwan, despite repeated warnings from China, making her the highest-level US official to visit the island in 25 years.

Pelosi's US Air Force-operated Boeing C-40C landed at Taipei's Songshan Airport on Tuesday night local time, marking the start of the third and most controversial leg of her five-country Asia tour.

The 82-year-old and her delegation of Democratic lawmakers were met by Taiwan Foreign Minister Joseph Wu and Sandra Oudkirk, the director of the American Institute in Taiwan, which serves as Washington's de facto embassy.

The trip has drawn outrage from Beijing, which views the self-governing island as a breakaway territory that will one day be reunited with the mainland.

Joe Biden Biden urged to use power to address mass incarceration before Trump takes office

Pelosi is the third-highest ranking official in the US government, behind President Joe Biden and Vice President Kamala Harris. For days, she has declined to confirm news reports that she would visit and Taiwan was not on her official itinerary.

People around the world monitored the progress of her flight on Tuesday, watching on flight tracking websites as her plane made its way from Kuala Lumpur toward Taipei. FlightRadar24 even crashed at one point as hundreds of thousands of users logged on to follow the "Pelosi flight".

The plane avoided the contested South China Sea and was escorted by eight US Air Force fighter jets as well as Taiwan Air Force fighter aircraft.

Tensions over Taiwan have not been as high since the 1990s, and it showed, as Chinese SU-35 fighter jets flew into the narrow Taiwan Strait, which separates the island from the mainland, shortly ahead of Pelosi's arrival.

Beijing had warned the United States that there would be a "very serious situation and consequences" if the visit went ahead. Foreign Ministry spokesman Zhao Lijian told the press in Beijing on Monday that it would be a "blatant interference in China's internal affairs."

A statement by the foreign affairs ministry bashed the "serious violation of the one-China principle and the provisions of the three China-US joint communiqués," saying it would have "a severe impact on the political foundation of China-US relations."

Donald Trump Trump orders Republicans to "kill" a bill aiming to protect journalists from government

China's leadership regards Taiwan as part of the People's Republic and rejects official contacts between its diplomatic partners and the government in Taipei. Taiwan, which has 23 million inhabitants, has long considered itself independent.

Pelosi's delegation is expected to stay overnight in Taipei City's Grand Hyatt Hotel, where protestors from the pro-China Alliance to Promote Chinese Unification had gathered. They were countered by the Taiwan State-Building Party, whose members held placards that read "Democracies Strong Together."

Pelosi released a statement after her dramatic landing, saying: "Our Congressional delegation’s visit to Taiwan honors America’s unwavering commitment to supporting Taiwan’s vibrant Democracy."

She also insisted the move "in no way contradicts longstanding United States policy," which is characterized by the balancing act of maintaining a close relationship that is, however, less than official diplomacy. An opinion piece in The Washington Post lays out her reasons in more detail.

Pelosi's visit has been criticized in some quarters as "reckless" and "unnecessary," seemingly coming against the advice of the Biden administration's national security advisors.

The California representative is expected to visit Taiwan's parliament on Wednesday and meet with Yu Shyi-kun, the legislature's leader, before holding talks with President Tsai Ing-wen.

Also on her schedule are meetings with Chinese, Hong Kong, and Taiwanese human rights activists. She is expected to depart for Seoul, South Korea in the early evening.