Suwat Donsakul, a naval commander in the southern province of Ranong, told AFP one Thai fisherman drowned and "31 people were taken into Myanmar", without specifying who had detained them.

Suwat said several Thai fishing boats were operating within Myanmar's waters at the time of the incident on Saturday.

The deceased "jumped into the water during the attack", he said.

Suwat said he had instructed local authorities to negotiate with their Myanmar counterparts to secure the release of the fishermen.

A spokesperson for Thailand's Ministry of Foreign Affairs told AFP that they would also engage in negotiations with the Myanmar side to secure their release.

AFP has reached out to Myanmar's junta government for comment.

The incident prompted the Ranong provincial fisheries department to issue a warning to fishers and boat owners to avoid areas near the Thai-Myanmar maritime border.

The fisheries department said in a statement that "Myanmar armed fishing boats" had attacked Thai fishing vessels around 20 kilometres (12 miles) west of Phayam island, off the Thai coast, without specifying the identity of the alleged attackers.

Its warning was to "all fishing operators and vessel owners to be cautious when navigating near the border".

Thailand and Myanmar share approximately 1,500 miles of land and maritime borders, including in the Andaman Sea.

According to a notice on the website of Thailand's fisheries department, Thai fishing boats have been illegally operating in Myanmar waters, raising tensions between the two countries.