SEOUL, Aug 3 (Reuters) - North Korea's foreign ministry on Wednesday criticised what it called U.S. "imprudent interference" in China's internal affairs over House of Representatives Speaker Nancy Pelosi's visit to Taiwan, the official KCNA said.

Pelosi arrived in Taiwan late on Tuesday on a trip she said shows an unwavering American commitment to the Chinese-claimed self-ruled island, but China condemned the highest-level U.S. visit in 25 years as a threat to peace and stability in the Taiwan Strait.

A North Korean foreign ministry spokesperson said they "vehemently denounce" any external force's interference in the issue of Taiwan and "fully support" China, its major ally and economic lifeline.

"It is the due right of a sovereign state to take counter measures against the moves of the outside forces openly interfering in its internal affairs and destroying its territorial integrity," the unidentified official was quoted by KCNA as saying.

China considers Taiwan part of its territory and has never renounced using force to bring it under its control. The United States warned China against using the visit as a pretext for military action against Taiwan.