Authorities in Beijing were investigating claims that unidentified North Koreans seized a Chinese fishing boat on May 6, local media reports.

According to Yu Xuejun, the boat’s owner, the vessel was seized by armed North Koreans in waters around 70 kilometers (40 miles) off the western coast and the kidnappers are demanding a ransom of 600,000 yuan ($98,000) for the 16 crew members.

Yu told AFP he was not certain of the kidnappers’ identities but suspected they were associated with the North Korean army. He added that he had been in contact with the 16 sailors as recently as Saturday and said they were in good health.

He posted details of the incident on the Internet out of frustration over an apparent lack of official action after reporting the armed hijacking to authorities.

The Chinese embassy in North Korea said they were “dealing with the matter”.

“We are currently investigating the boat owner’s claims,” a section chief for the state border detachment in the northeastern port city of Dalian told AFP.

Last year, twenty-nine Chinese fishermen were also kidnapped by unidentified North Koreans who had demanded a 1.2 million yuan ransom. The men were returned without ransom after the Chinese foreign ministry said it contacted Pyongyang over the case.