HANOI, July 12 (Xinhua) — Representatives from the Vietnamese foreign ministry's Consular Department have met with officials of the Thai Embassy in Hanoi to protest the use of violence against Vietnamese fishermen and requested Thailand's foreign ministry to investigate the incident.

Vietnam said Thai navy have fired at three Vietnamese fishing boats with 18 fishermen on board, injuring two fishermen, while two other Vietnamese fishing boats sank while being escorted to land, leaving a captain missing.

The remaining 15 crew members were taken ashore by Thai naval vessels, the Vietnamese Embassy in Thailand has said.

Deputy Spokesperson of Vietnam's Ministry of Foreign Affairs Pham Thu Hang, while answering reporters' question on Monday about the incident, said the Vietnamese embassy has taken necessary citizen protection measures for the detained Vietnamese fishermen.

The embassy has also urged the Thai side to urgently search for the missing sailor, Hang said, adding that the Thai side said they had dispatched helicopters and ships to look for the missing captain.

According to the deputy spokesperson, the Vietnamese foreign ministry is also coordinating with relevant domestic agencies to obtain more information in order to address the incident.

She noted that officials from the Vietnamese embassy visited the wounded sailors, who were confirmed as being in stable conditions on Monday, reported Vietnam's state-run news agency on Tuesday.

The incident took place at around 14:00 local time (0700 GMT) last Friday, according to the Vietnamese embassy.

The fishing boats were chased off by Thai naval police after they were allegedly found illegally operating in Thailand's waters earlier on the same day, according to Nguyen Hai Ngoc, first secretary of the Vietnamese embassy.

Thai media reported on Monday that the Thai navy have arrested the crew members of three Vietnamese trawlers for allegedly illegal fishing in Gulf of Thailand.