Her arrival sparked immediate criticism from Beijing, with China's foreign ministry saying it seriously violated China's sovereignty and territorial integrity. State media announced military excercises later this week and Chinese war planes flew over Taiwan Strait before her arrival.
Pelosi was on a tour of Asia that includes announced visits to Singapore, Malaysia, South Korea and Japan. Her stop in Taiwan had not been announced but had been widely anticipated.
China claims self-ruled Taiwan as its own, and a foreign ministry spokesman said earlier this week that any visit by Pelosi would be "a gross interference in China's internal affairs" and warned that "the Chinese People's Liberation Army will never sit idly by."