Taiwan has accused a Chinese-owned ship of severing a critical data cable off its northern coast on Friday. Officials in Taipei discovered that four cores of an international submarine cable, which transmits data to America’s AT&T, were left ruptured early on Jan 3.

Taiwan suspects that China was behind the cutting of an international undersea telecom cable early Friday morning.

The telecommunications cable connecting Taiwan to the mainland has been cut. Due to bad weather, a suspected vessel—a tanker under the Cameroonian flag—could not be detained and continued its journey to South Korea.

Some security analysts say it's possible China is to blame for the cutting of an undersea cable off Taiwan's north coast on Friday. The damage did not affect Taiwan, but experts say it could be a sign Beijing is trying to figure out how to isolate the country from the rest of the world.