SINGAPORE — A Chinese national has been sentenced to three years in prison for damaging an undersea cable connecting Taiwan's main island and the Penghu islands in the Taiwan Strait.

The man, identified by his surname Wang, was the captain of the Togolese-registered vessel Hong Tai 58.

The Tainan District Court's verdict on Thursday marks the first sentencing after reports in recent years of undersea cables around Taiwan being severed.

Taipei has accused Beijing of sabotaging its cables, describing it as a "grey zone" tactic to pressure the self-ruled island, which China claims as its territory.

But China has denied its involvement, calling the incidents "common maritime accidents" that have been "exaggerated" by Taiwanese authorities.

Undersea cables - insulated wires laid on the seabed - carry nearly all of the world's internet traffic.

An estimated 150 to 200 faults occur across the world's undersea cable systems every year, according to the International Cable Protection Committee.

Taiwan has 10 domestic and 14 international undersea cables.

The damage to cables linking Taiwan to the Penghu islands "seriously interferes with the government and society's operations", the court said in a statement about Thursday's sentencing.

"The impact is enormous, and the defendant's actions should be severely condemned."

In February, Taiwan's coast guard spotted Hong Tai 58 anchored off the island's southern coast for several days and broadcasted warnings asking it to leave.

Minutes after Hong Tai 58 departed the waters in the early hours of 25 February, the coast guard learned that an undersea cable in the area had been severed.

Hong Tai 58 was escorted back to Taiwan for investigation, and its crew of eight Chinese nationals were detained.

Mr Wang is the only one to face charges, and the remaining crew members have reportedly been sent back to China.

While Mr Wang initially denied damaging the undersea cables, he said during his trial that he "might have broken the cable".

Mr Wang, who did not appoint a lawyer, told the court that the rough waters had made navigation tricky, and he instructed the crew to drop the anchor without knowing that the area contained undersea cables.

However, prosecutors argued that he had intentionally damaged the cable, pointing to electronic charts on the ship clearly showing the cable's location.

Hsu Shu Han, a prosecutor in the case, told BBC Chinese in May that the vessel was "highly suspicious". It had only one cargo record in the past year and was in poor condition, "but they were still sailing that ship around the Taiwan Strait", he said.

Mr Hsu also said the ship had gone by multiple names, and that Mr Wang had deliberately concealed information about the vessel's owner, who has yet to be identified.

The Coast Guard told the court that ships typically move in a circular motion around the anchor, but the Hong Tai 58 had dragged its anchor straight across the seabed.

Prosecutors said the ship had sailed in a zigzag pattern around the cable.

The damaged section of the cable also matched the ship's anchoring location and showed signs of being snagged by an external force.

Between 2019 and 2023, there were 36 cases of undersea cables being damaged by external forces, according to Taiwan authorities.

Taiwan has been increasingly wary of potential sabotage, especially from China. In January, it accused a Chinese-owned ship of damaging an undersea cable near its northern coast - claims that have been denied by the ship's owner, Reuters reported.

Kuan Bi-ling, Taiwan's ocean affairs council minister, said that Hong Tai 58 was among the 52 vessels that Taiwan had been monitoring for suspicious activities.

Such suspicions are not just surfacing in Taiwan: Last November, a Chinese carrier was accused of severing two fibre-optic undersea cables in the Baltic Sea. But a Swedish probe earlier this year said it found no conclusive evidence to suggest this - though a separate investigation remains under way, said Reuters.

"Some scholars have said that World War III could begin with the cutting of undersea cables. I think that's quite realistic," Herming Chiueh, deputy minister of Taiwan's Ministry of Digital Affairs, told BBC Chinese.

"From the Ministry's perspective, our job is to ensure timely reporting and response for these critical infrastructures."

Mr Hsu said that Mr Wang's phone records showed no links to Chinese authorities, and there was no direct evidence proving that the crew had been acting under Chinese government orders.

Tensions have ratcheted between Taiwan and China over the past year. Taiwanese President William Lai has adopted a tough stance against Beijing, calling it a "foreign hostile force". Meanwhile, China has held regular drills around Taiwan to simulate a blockade of the island. — BBC