BANGKOK- A total of 13 Chinese sailors, who were on two ships hijacked by drug traffickers last week, were confirmed dead after investigators found another body on Mekong River in north Thailand's Chiang Rai province, local authorities told Xinhua on Monday.

Searchers found the body in nearby Chiang Khong District early on Monday, said Seramsak Seesan, chief of Chiang Rai's Chiang Saen District, where the other bodies were found. The two hijacked Chinese-flagged ships reportedly had 13 crew members.

Investigators suspect that a drug ring of Tai Yai ethnic group led by No Kham was responsible for the incident, Seesan told Xinhua in a telephone interview.

Autopsies are being conducted in Chiang Saen Hospital. Relatives of the sailors will arrive on a later date to cooperate in investigation and claim the bodies, he said.

This was the first time a commercial ship was hijacked by drug traffickers, Seesan added.

A committee of police, military and local authorities are further investigating the case, he said.