The collision between a mystery Chinese warship and a Taiwanese freighter first reported last week had led to an hour long stand-off last, which ended after the intervention of the Taiwan coast guard.

Fu Shih-hour, the captain of cargo vessel Yutai No.1 which was involved in the collision, told Bloomberg News on Tuesday that the captain of the Chinese warship told him to divert his vessel to the port of Xiamen. He then radioed the Taiwanese coast guard for help.

Fu told Bloomberg News from the southern Taiwanese port of Kaohsiung, “When they arrived, the coast guard told the Chinese captain very clearly that we were in international waters and that we were under no obligation to follow their orders. It’s not as if we were in Chinese waters and had to listen to them. The other captain wasn’t happy about it, but had to begrudgingly accept it.”

Yutai No. 1 had collided with a mysterious Chinese warship around 20 nautical miles southeast of Kinmen Island, which is controlled by Taiwan, on July 31. The ship’s identity hasn’t been confirmed yet as Fu, and the Taiwan coast guard ships that went to assist him, weren't able to identify the vessel. Fu estimated the ship to be around 100 meters (330 feet) in length, in the dark. Though the automatic identification system (AIS) of the vessel wasn’t turned on, Fu positively said that it was military ship travelling very fast. He noted that navy ships don’t usually use AIS.

Reports had been circulating in the media since the collision with Taipei-based China Times saying the ship may have been the Longushan, China’s largest domestically designed amphibious warship, with a length of 210 meters. But Taiwanese media had reported a Chinese frigate was also in the area around that time.

China has increased the military pressure on Taiwan recently with Chinese military warships transiting the geopolitically significant Taiwan Strait. The U.S. too sent its warships through the busy shipping lane, in a bid to show its support for Taiwan.

Chinese Coastguard ship patrols the South China Sea A still image taken from video shows a Chinese coast guard vessel sailing in the South China Sea, about 130 miles off the shore of Vietnam, May 14, 2014. Photo: REUTERS/Reuters TV

The tension in the area can be traced back to Taiwan’s current president Tsai Ing-wen coming in to power in 2016. She has actively pushed for Taiwan's independence, with thousands marching to support the independence vote in Taiwan last year.

China warned U.S. last month that it was ready to go to war to stop Taiwan from gaining independence. A defense white paper released by Beijing last month said about China’s determination to stop Taiwan from gaining formal independence at any cost.

Fu, 72, played down the political side of the incident, saying it was just a simple accident at sea and shouldn’t be blown out of proportion.