Taiwanese authorities said they had detained a cargo ship crewed by Chinese nationals, which investigators believe may have severed an undersea communications cable near the island on Tuesday. It was the latest in a series of murky incidents that have prompted theories that China and Russia may be turning to cable sabotage as a form of harassment at sea.
The cable that was damaged connected Taiwan to the Penghu Islands, which belong to Taiwan and lie about 30 miles west of the main island. Taiwan’s Coast Guard said that it was still investigating the latest incident and had not reached any conclusions about whether the severing was deliberate or accidental.
But Ou Yu-fei, a press officer for the coast guard, said initial clues pointed to the detained ship, a dilapidated cargo carrier that used more than one name, including “Hong Tai 58.” The ship had Chinese funding, the coast guard said in a statement.
“This was the only vessel in the area — that’s our judgment,” Mr. Ou said in a telephone interview, citing radar records of where the cable break occurred. “We’re not ruling out the possibility that it was engaged in an act of sabotage. We go by the evidence. It’s too early to reach conclusions.”
Mr. Ou added that the ship may have used a false registration number and appeared to have suddenly had its name changed, among other details.
The ship may have severed the cable — accidentally or deliberately — around the time that a Chinese coast guard ship warned it to leave the vicinity in the early hours of Tuesday, he said. “It is possible that it used the time when it was leaving to carry out sabotage,” he said.
The cable that was broken is one of several connecting the Penghu Islands, also called Pescadores, to the main island. Communications were quickly rerouted after the damage was detected, and there was no major outage, the authorities said.
Taiwan usually depends on undersea cables for its internet connections with outlying islands, such as the Penghu Islands, as well as for its connections to the rest of the world. Cables can be severed by natural factors like earthquakes or aging, but the most common cause is when ships drag anchors or fishing equipment that scrapes the sea floor.
Recent incidents off Taiwan and in the Baltic Sea have raised suspicions among some officials and experts that China and Russia may sometimes deploy commercial cargo ships or oil tankers to deliberately cut cables by dragging their anchors.
Two years ago, a cable between Taiwan and Matsu Island was severed. Earlier this year, a digital cable connecting Taiwan with South Korea, Japan, China and the United States was damaged, and Taiwanese authorities said that a Chinese ship may have dragged its anchor across the cable, either accidentally or deliberately. In November, two fiber-optic cables under the Baltic Sea were severed, and countries in that region have been investigating a Chinese-flagged commercial ship that may have been involved.
In January, two cables between Taiwan and Matsu suffered damage, but officials quickly said that the cause was natural deterioration of the cables.
Since those incidents, Taiwan’s government has stepped up monitoring of its subsea cables. The ship suspected of involvement in the latest severing had been watched by Taiwan’s Coast Guard since Saturday, partly because it seemed to be lingering in areas with undersea cables off Taiwan’s southern coast, said Mr. Ou, the press officer.
At about 2:30 a.m., a Taiwanese coast guard patrol ship that was in the cargo carrier’s vicinity — about seven miles out of a port — moved in closer and ordered it to leave, because it was too near an area with undersea cables and had its anchor down, Kuan Bi-ling, the minister of Taiwan’s Ocean Affairs Council said in an online statement.
Over half an hour later, the ship pulled up its anchor and began moving, Ms. Kuan said. But at 3:24 a.m., the coast guard received a report that the cable had been cut, and brought the ship into port, where it is being investigated. The coast guard said that it has also sent the case to prosecutors for additional inquiries.
