TAIPEI (Reuters) - Taiwan sent aircraft on Monday to shadow China air force fighter jets as they flew through the Bashi Channel to the south of the island, its defense ministry said, the latest such incident to add to tension between Taipei and Beijing.

China sent an unspecified number of Xian H-6 bombers, Su-30 fighter jets and Y-8 transport aircraft over the waterway on their way to the West Pacific Ocean, the Taiwan ministry said.

They were followed by Taiwan jets until the mainland aircraft returned to base, it said in a statement.

Taiwan on March 21 sent ships and aircraft to shadow a Chinese aircraft carrier group that sailed through the narrow Taiwan Strait.

Taiwan is one of China’s most sensitive issues and a potential military flashpoint.

The Chinese military movements come during a time of heightened tension between Beijing and the self-governed island and follows strong warnings by Chinese President Xi Jinping against Taiwan separatism.

China claims Taiwan as its own and considers the island a breakaway province. Xi said last week Taiwan would face the “punishment of history” for any attempt at separatism.

China’s hostility towards Taiwan has grown since Tsai Ing-wen from the pro-independence Democratic Progressive Party won presidential elections on the island in 2016.

Meeting New Taipei City Mayor Eric Chu in Shanghai on Monday, the newly appointed head of China’s policy-making Taiwan Affairs Office, Liu Jieyi, said China was clear in its opposition to Taiwan independence, Chinese state television said.

China hopes both sides of the Taiwan Strait can work together for the peaceful development of relations and “jointly promote the process of the peaceful reunification of the motherland”, Liu told Chu, state television added.

The New Taipei City government said in a statement that Chu, from the China-friendly opposition Nationalist Party, told Liu they hoped for peaceful cooperation.

“Although the political situation has changed, what people hope for most is peace,” said Chu, who Tsai defeated for the presidency two years ago.

While China insists it has no hostile intent, its military exercises and patrols around Taiwan, and in the busy South China Sea waterway, have touched a nerve in the region and in the United States.

U.S. Deputy Assistant Secretary of State Alex Wong angered Beijing during a recent visit to Taiwan by saying the U.S. commitment to the island had never been stronger.

Beijing is already furious about a law signed two weeks ago by U.S. President Donald Trump that encourages the United States to send senior officials to Taiwan to meet counterparts and vice versa.