Taiwan is investigating whether a Chinese-owned ship was involved for destroying one of the underwater cables that connects Taiwan to the internet, the latest reminder of how susceptible Taiwan’s crucial infrastructure is to Chinese attack.

The incident comes as Europeans are concerned about apparent acts of sabotage, especially those targeting underwater communication cables. Two fiber-optic cables under the Baltic Sea were broken in November, causing officials from Sweden, Finland, and Lithuania to block a Chinese-flagged commercial ship in the area for several weeks due to its potential involvement.

Communications in Taiwan were promptly diverted when the damage was discovered, and there was no significant disruption. Chunghwa Telecom, the island’s principal telecommunications operator, got information on Friday morning that the Trans-Pacific Express Cable had been destroyed. The cable also links South Korea, Japan, China, and the United States.

That afternoon, Taiwan’s Coast Guard halted a cargo vessel off the northern city of Keelung, near where half a dozen cables come ashore. A Hong Kong business owned the yacht, which was crewed by seven Chinese nationals, according to the Taiwan Coast Guard Administration.

The broken cable is one of over a dozen that help keep Taiwan connected. These weak wires are vulnerable to breaking from anchors dragged around the sea floor by the many ships that frequent the bustling waterways near Taiwan.

Analysts and authorities believe that while it is impossible to show if the damage to these cables was purposeful, such an act would fit with China’s pattern of intimidation and psychological warfare aimed at undermining Taiwan’s defenses.

Taiwan stated that the cargo vessel it detained was registered under both Cameroon and Tanzanian flags. “The possibility of a Chinese flag-of-convenience ship engaging in gray zone harassment cannot be ruled out,” the Coast Guard Administration stated in a statement Monday.