Taiwan’s coastguard has seized a cargo ship along with its Chinese crew following damage to an undersea cable in the Taiwan Strait on Tuesday. Authorities have not ruled out the possibility that the incident was a deliberate “grey zone” action.

In a statement, the coastguard said, “Whether the cause of the undersea cable breakage was intentional sabotage or a simple accident remains to be clarified by further investigation.” It also noted, “It cannot be ruled out that it was a grey-zone intrusion by China.”

The term “grey zone” refers to hostile interference that falls short of open warfare.

Taiwan’s coastguard reported that Chunghwa Telecom alerted it early Tuesday about damage to a communications cable linking Taiwan’s main island with Penghu in the Taiwan Strait.

A coastguard spokesperson stated that Taiwanese authorities had closely monitored areas near undersea cables. On February 22, a cargo ship was detected stopping “very close” to the Penghu cable off the coast of Tainan. On Tuesday, coastguard vessels were dispatched around 2:30 a.m. and observed the ship dropping anchor. About half an hour before Chunghwa Telecom reported the cable had been cut, the boat began moving northwest, the spokesperson added.

According to the coastguard, the cargo ship did not respond to communication attempts via speaker and radio. It was eventually intercepted and escorted back to Anping port shortly after midday. Footage released by the coastguard shows officers boarding the cargo vessel.

The detained ship is registered under a Togolese flag, but Taiwan’s coastguard suspects it is likely a flag of convenience. All eight crew members on board are Chinese nationals. The actual ownership of the cargo ship remains unclear, as tracking and registration data link its maritime identification number to at least three different ship names. The coastguard described the vessel as “China-funded” but did not provide further details.

Taiwan has compiled a watchlist of over 50 ships that it closely monitors. These vessels are believed to be owned by Chinese companies but operate under flags of convenience, including from Togo. Some of these ships have spent extended periods in or near Taiwan’s territorial waters. This list was first reported by the Financial Times and later confirmed by The Guardian.

Despite the undersea cable damage, Chunghwa stated that a backup cable had been activated, ensuring no disruption in communication.

This is the latest instance of undersea cable damage near Taiwan in recent years. In January, Taiwanese authorities launched an investigation into a Chinese-owned, Cameroon-registered vessel, Shunxing 39, suspected of dragging its anchor and damaging a cable northeast of Taiwan that connected to the US.

Taiwan’s coastguard ordered the ship to return for inspection, but rough weather prevented them from boarding. The vessel then left the area and sailed to South Korea.

A similar incident occurred in February 2023 when two undersea cables near the Matsu Islands, close to China’s mainland, were severed, cutting off internet access for residents for weeks. Two Chinese ships were blamed for the damage, which happened in two incidents nearly a week apart. However, the Taiwanese government did not officially accuse Beijing of intentional sabotage.