BANGKOK - The Thai police has launched an investigation and were hunting for the attackers on two Chinese cargo ships five days ago that left 11 Chinese dead and two missing, an official at China's consulate general in Chiang Mai said Sunday.

China's consulate general in this northern Thailand province has been dealing with this incident, the official added.

Two cargo ships, the Hua Ping and Yu Xing 8, were attacked in the golden triangle area of the Mekong River on October 5, China's Foreign Ministry said in a statement on its website Sunday.

Of the six Chinese on the Hua Ping, five were found dead and one was missing and of the seven Chinese on the Yu Xing 8, six were killed and one was missing, according to the statement.

A Bangkok Post report later Sunday said that three bodies of Chinese men, with their hands tied and handcuffed behind their backs, were found floating on the Mekong River in Chiang Rai's Chiang Saen district Friday and another nine bodies were found the day after.

The report said the bodies have been sent to Chiang Saen hospital for an autopsy and it blamed drug traffickers who wanted ships to smuggle drugs into Thailand from Myanmar for hijacking the two Chinese-flagged cargo ships on Wednesday and killing the captain and crew.  

The Chinese Foreign Ministry in the statement said it has asked the Chinese embassy in Thailand and consulate general in Chiang Mai to investigate the incident immediately and spare no efforts to search for the missing.  

Chinese diplomats in Chiang Mai have arrived at the site to investigate. The Chinese embassy in Thailand is having close contact with the Thai side to get further information, according to the statement.

It has also asked "relevant countries" to take effective measures to improve the protection of Chinese ships and sailors in the Mekong River, according to the statement.

The Chinese Foreign Ministry also said leaders of the Communist Party of China Central Committee and the State Council are paying close attention to the matter.

The ministry has urged the "relevant countries" to immediately look into the incident, determine the truth and bring the criminals to justice as soon as possible.