A US senator who sits on the Senate's Commerce and Armed Services Committees arrived in Taiwan on Thursday, the third such visit this month and defying pressure from Beijing for such trips not to take place.
China, which claims Taiwan as its own territory against the strong objections of the democratically-elected government in Taipei, launched military drills near the island after US House of Representatives Speaker Nancy Pelosi came in early August.
Senator Marsha Blackburn arrived in Taiwan's capital Taipei on Thursday on board a US military aircraft, live television footage from the downtown Songshan airport showed.
Taiwan's official Central News Agency said she was due to meet President Tsai Ing-wen on Friday.
Blackburn earlier in August voiced support for Pelosi's trip to Taiwan.
"We must stand with Taiwan, and I applaud Pelosi for not backing down to Biden or the CCP," Blackburn said in a Twitter post at the time, referring to China's ruling Communist Party.
Pelosi's visit infuriated China, which responded with test launches of ballistic missiles over Taipei for the first time, and by ditching some lines of dialogue with Washington, including theatre military talks and on climate change.
She was followed around a week later by five other US lawmakers, with China's military responding by carrying out more exercises near Taiwan.
The United States has no formal diplomatic relations with Taiwan but is bound by law to provide the island with the means to defend itself.
China has never ruled out using force to bring Taiwan under its control.
Taiwan's government says the People's Republic of China has never ruled the island and so has no right to claim it, and that only its 23 million people can decide their future.