Taiwan's coast guard said it detained a China-linked cargo ship on Tuesday after a nearby undersea cable to the Penghu Islands in the sensitive Taiwan Strait was disconnected.
Taiwan, which China claims as its own territory, has repeatedly complained about "grey zone" Chinese activities around the island, designed to pressure it without direct confrontation, such as balloon overflights and sand dredging.
Taipei was alarmed after a Chinese-linked ship was suspected of damaging another cable earlier this year, prompting the navy and other agencies to step up efforts to protect the undersea communication links, which are vital to the island's connections to the rest of the world.
The coast guard said it dispatched three vessels to detain the Chinese-crewed Hong Tai 58, registered in Togo, which dropped anchor near the sea cable off the southwestern coast of Taiwan around the time it was disconnected.
The vessel is a Chinese-linked ship carrying a flag of convenience, the coast guard said, meaning it is registered to a country other than that of its owner.
"All eight crew members are Chinese nationals and (we) do not rule out the possibility of the Chinese activity of grey-zone harassment," the coast guard said in a statement, adding that further investigation is needed.
China's Taiwan Affairs Office did not immediately respond to a request for comment. Reuters was not able to locate a contact for the ship's owner.
Communications between Taiwan and other offshore islands, including Penghu, were not affected after services were redirected to other cables, the digital ministry said.
A senior Taiwan security official, speaking anonymously because of the sensitivity of the issue, told Reuters the government is handling the case as a national security matter.
"It's beyond the normal range," the official said, pointing to the course of the boat, which had lingered in the waters just southwest of Taiwan since Saturday and did not respond to repeated calls by the coast guard.
Taiwan has reported five cases of sea cable malfunctions this year, compared with three each in 2024 and 2023, according to the digital ministry.
In 2023, two undersea cables connecting the Matsu islands were cut, disconnecting the internet. Taiwan authorities said that two Chinese vessels caused the disruption, but that there was no evidence Beijing deliberately tampered with the cables.
(This story has been refiled to say Tuesday, not Wednesday, in paragraph 1)
