TAIPEI, Aug 3 (Reuters) - Taiwan president's Tsai Ing-wen on Wednesday thanked visiting U.S. House speaker Nancy Pelosi for her concrete actions to support Taiwan at this critical moment and said the island will not back down in the face of heightened military threats.

The pair met in Taipei on Wednesday as part of Pelosi's visit to the island which has drawn fierce criticism from China, and has prompted Beijing to announce a raft of military exercises and summon the U.S. ambassador.

Tsai also told Pelosi on Wednesday that she is one of Taiwan's most devoted friends and thanked her for her unwavering support on the international stage.

Tsai added that Taiwan is a reliable partner of the United States and will continue to work with the U.S. to strengthen collaboration in security, economic development and supply chains.