Image copyright EPA/Shutterstock Image caption Surachai Sae-Dan has been missing since 12 December

The mutilated bodies of two men found last month in north-east Thailand have been identified as aides of Surachai Sae-Dan, a prominent opponent of the Thai monarchy, police have confirmed.

The pair were found by the Mekong river, their faces disfigured and their stomachs stuffed with concrete blocks.

They and Mr Surachai were members of a group which fled into exile in Laos in 2014 after Thailand's military coup.

All three disappeared on 12 December. Mr Surachai's fate is unknown.

The campaign group Human Rights Watch says five Thai government critics who had been living in Laos have gone missing in the past two years.

Death squad fears

The bodies were found towards the end of December, one of them apparently floating in the river. Both were wrapped in sacks and fish nets tied up with rope.

They were identified after DNA tests as Kraidej Luelert and Chatchan Buphawan.

Unconfirmed reports say a third body was found at the same time but then lost again.

The incident has raised concern among activists about kidnappings by vigilantes or officially sanctioned death squads, though Thai officials have denied any involvement in the disappearances.

The country has tried unsuccessfully to extradite a number of activists who fled abroad since the coup.

Surachai Sae-Dan, whose real name is Surachai Danwattananusorn, has been an outspoken critic of the Thai military and monarchy since the 1970s.

In his late seventies, he has served several prison terms including under the country's strict lese majeste laws for insulting the monarchy.

He was jailed most recently in 2012, but given a royal pardon the following year.