Two Chinese fishermen have drowned while being chased by Taiwan’s coastguard off the coast of Taiwan’s Kinmen archipelago, the coastguard has said.

The deaths are unusual despite the level of Chinese activity in the waters near Kinmen, which is closer to China than it is to Taiwan’s main island.

China claims all of Taiwan as part of its territory.

China’s Taiwan affairs office strongly condemned the deaths and called for an investigation, saying “such a malicious event during the spring festival seriously hurts the feelings of compatriots on both sides of the Taiwan Strait”.

Both China and Taiwan are celebrating the Lunar New Year holiday.

The statement accused the ruling Democratic Progressive Party in Taiwan of using “all sorts of excuses to forcefully inspect Chinese fishing vessels, and using violent and dangerous methods towards Chinese fishermen”.

The unnamed Chinese vessel had been sailing about one nautical mile off the coast of an islet of Kinmen island, Taiwan’s coastguard administration said in a statement.

The Chinese vessel attempted to flee but capsized.

Four fishermen fell into the water and two survived and are in “good shape”, while resuscitation efforts on the other two failed, the vice captain of the coastguard in Kinmen, Chen Jien-wen, told a local TV channel.

The coastguard said the case has been reported to the Kinmen prosecutor’s office, and the fishermen’s families were being contacted via official channels.

Taiwan’s head of the mainland affairs council, Chiu Tai-san, who oversees the island’s relations with China, told reporters on Thursday morning that “we keep a certain level of contact with the other side and our coastguard, and will promptly let them know of related developments”.

Kinmen is in the Taiwan Strait that separates China and Taiwan. From some parts of the archipelago, the southern Chinese city of Xiamen is visible to the naked eye.

Kinmen residents in recent years have reported seeing an increase in sand dredger vessels from China, which take sand from the ocean floor, as well as fishing ships, close to its coast.

At times, dozens of the ships can be seen from the island.