BEIJING, July 31 (Reuters) - China will "resolutely safeguard national sovereignty and territorial integrity", an air force spokesman said on Sunday, referring to Taiwan, as tensions rise over the self-ruled island.

Air force spokesman Shen Jinke was quoted by state media as saying at a military airshow that the air force has many types of fighter jets capable of circling "the precious island of our motherland".

U.S. House of Representatives Speaker Nancy Pelosi, number 3 in the line of presidential succession, signalled on Friday she was embarking on a trip to Asia. She did not mention Taiwan, but speculation of a visit there has intensified in recent days, fuelling tensions beyond the Taiwan Strait.

Beijing claims democratically ruled Taiwan as a Chinese province.

Chinese President Xi Jinping warned his U.S. counterpart Joe Biden on Thursday that Washington should abide by the one-China principle and "those who play with fire will perish by it."

Shen said on Sunday: "The air force has the firm will, full confidence and sufficient capability to defend national sovereignty and territorial integrity."

White House national security spokesperson John Kirby said on Friday the United States has seen no evidence of looming Chinese military activity against Taiwan.