Taiwan said it detained a Chinese-linked ship suspected of cutting an undersea cable on Tuesday.It's still investigating if the incident was sabotage but warned of "gray zone" tactics from China.That mirrors a dilemma faced by NATO in the Baltic Sea with vessels linked to China and Russia.After months of suspecting that Chinese-linked ships had damaged its undersea cables, Taiwan said it might have caught a vessel in the act.The Taiwanese coast guard released a statement on Tuesday saying it detained the Hongtai, a Togolese-flagged cargo ship, after a local telecom firm reported cable damage off the island's west coast.It said the ship had been loitering in those waters since Saturday, and that the coast guard pinged the vessel seven times but received no response.Taiwanese telecom firm Chunghwa then reported in the early hours of Tuesday that a cable to the nearby Penghu Islands had been severed.The coast guard said its officials arrived at the location and found the Hongtai anchored near the damaged cable. The agency said it "stopped the 'Hong' ship in the act."Its statement added that while registered under the Western African nation of Togo, the ship bore Chinese words on its hull and all eight of its crew members were Chinese nationals.A dilemma like NATO'sTaiwan's incident closely echoes the subsea cable damage in the Baltic Sea that's been plaguing NATO, though there's no evidence linking the incidents in both regions.Western nations have long suspected that the damage in the Baltics is the result of sabotage. In December, Finland accused the Russia-linked vessel Eagle S of deliberately dragging its anchor on the seabed to sever the Estlink 2 power cable.And when two other cables in the Baltic Sea were cut in November, a Chinese cargo ship was found nearby.European NATO countries have since responded by forming a coalition to monitor the Baltic Sea with drones, marine aircraft, and ships.But it's been difficult for the Nordic nations and their allies to pin down who's behind the damage, especially since they were caused by civilian ships. For example, with no public connection between the Russian government and the Eagle S, which is owned by a UAE-registered company, the Kremlin has denied any ties to cable cutting in the Baltics.The lack of official links to Moscow has led to European leaders dubbing the vessels as Russia's "shadow fleet" which they say is also used to transport sanctioned oil and gas.The Hongtai appears to have multiple namesIn Taiwan's case, the coast guard highlighted the problems it faced in identifying the Hongtai. The agency said the ship told authorities it was the Hongtai 168 but that its vessel identifier listed it as the Hongtai 58.Local outlet Central News Agency also published a photo taken by its reporter of the detained ship's stern. The image shows a different name: the Shanmei 7.Taiwan's coast guard said it's investigating whether the incident involved sabotage or was purely an accident."It cannot be ruled out that it was a gray zone intrusion operation by China," its statement said, using a term describing hostile acts of subversion or sabotage that fall short of open war.When reporters asked China's Foreign Ministry on Tuesday if it could comment on the Hongtai's detainment, a spokesperson said: "I'm not familiar with what you mentioned, and this is not a question related to foreign affairs."Why the cables matter to Taiwan and ChinaThe detaining of the Hongtai, which Taiwan said is now held at the Anping port, comes as Taipei has voiced suspicions for over a year that Chinese ships were damaging its undersea cables.In January, Taiwan's coast guard reported that the Shunxin39, a Chinese-linked freighter on its way to South Korea, could have severed a subsea cable and ignored instructions to turn around for an investigation."The proximity between the different 'accidents' shows that there is indeed a pattern," Benjamin Blandin, a researcher who studies Asian maritime security at the Yokosuka Council on Asia-Pacific Studies, told Business Insider.These cables often carry vital internet access or electricity. In 2023, Taiwan said Chinese ships had damaged two subsea internet cables to the outlying Matsu Islands, which suffered from limited online access afterward."This was not just any random cable, but one connecting the north of the main island to an archipelago off the coast of Fuzhou," Blandin said. "That has strategic importance as a forward operating base and a way to monitor China."Blandin said Tuesday's incident involved a cable linked to the Penghu Islands, which also serve as a base for observing Chinese movements."If one day China takes these islands, or the Wuqiu and Kinmen Islands, Taiwan will be partially blind," he said.