Chinese and Taiwanese warships played high-seas “cat and mouse” on Sunday ahead of the scheduled end of four days of unprecedented Chinese military exercises launched in reaction to a visit to Taiwan by the U.S. house speaker. Nancy Pelosi’s visit last week to the self-ruled island infuriated China, which responded with test launches of ballistic missiles over the island’s capital for the first time and the cutting of communication links with the United States.

Some 10 warships each from China and Taiwan sailed at close quarters in the Taiwan Strait, with some Chinese vessels crossing the median line, an unofficial buffer separating the two sides, a person with knowledge of the matter said.