China has announced the seizure of a Taiwanese fishing boat with five crew members aboard for allegedly fishing illegally in its territorial waters on Tuesday night. Taiwan has requested the release of the vessel and the men, which include two Taiwanese and three Indonesians, currently held at Weitou, a port in southeast China.

Taiwanese officials confirmed to the BBC that the boat was seized within China’s territorial waters, approximately 2.8 nautical miles (5.1 km) off the coast, and was operating during China’s annual summer fishing ban from May to August.

“The fishing vessel violated the fishing moratorium regulations and trawled illegally within the prohibited area,” said Liu Dejun, spokesperson for the China Coast Guard. He also accused the crew of using incorrect fishing gear and “damaging marine fishery resources.” Taiwan has yet to respond to these accusations.

Such altercations are common in the contested 110-mile strait that separates China and Taiwan. China claims self-ruled Taiwan and the strait as its exclusive economic zone, though other countries navigating these waters, including Japan and the United States, do not recognize this claim. The Chinese military has increased pressure on Taiwan in recent years.

Since 2003, Chinese authorities have seized and detained 17 Taiwan-registered vessels for fishing during the summer ban, according to Taipei’s data. This year alone, Taiwan has detained five Chinese boats for similar reasons.

Taiwanese authorities reported that at 20:04 local time (12:04 GMT) on Tuesday, the captain of the seized boat alerted them that officers from two Chinese coast guard vessels had boarded and detained the vessel. In response, three Taiwanese coast guard ships were dispatched to rescue the boat, leading to a brief but tense standoff. However, they did not pursue the Chinese vessels due to the approach of four additional Chinese coast guard ships, aiming to avoid escalating tensions.

The Chinese coast guard reported that both sides used loudspeakers to demand the release of the boat and to ask the other side not to interfere.

“There were 40 to 50 fishing boats out at sea at the time. I don’t know why they targeted my boat,” the owner of the fishing vessel told local media. “This never happened before; in the past, they would just chase you away if you got too close.”