BANGKOK (Reuters) - Laos should release a prominent rights activist who went missing this month, an international human rights group said on Thursday, although authorities there have said they do not know where he is or who was responsible for his disappearance.
Sombath Somphone, 60, disappeared on December 15 in the Lao capital, Vientiane, after being stopped by police while driving his jeep from the development agency he founded, human rights groups say.
"Circumstances surrounding the case including security camera footage, indicate Lao authorities took him into custody, raising concerns for his safety," New York-based Human Rights Watch said in a statement.
"The Lao government needs to immediately reveal Sombath's location and release him," said Brad Adams, the group's Asia director.
The United States has also voiced concern about the disappearance of Sombath, who received the Ramon Magsaysay Award for community leadership in 2005 and worked to promote education and development in poverty-stricken Laos. The award is often described as Asia's equivalent of the Nobel Prize.
The landlocked Communist country has little tolerance for dissent and this month expelled the director of a Swiss development organisation for criticizing the country's one-party regime in a letter to donors.
In a rare statement posted by official media on Wednesday, the Lao Ministry of Foreign Affairs said traffic police had stopped Sombath on December 15 in the course of routine checks but unknown men had taken him away shortly after that.
"It may be possible Mr Sombath has been kidnapped perhaps because of a personal conflict or a conflict in business," the ministry said.
"The authorities are not in a position to say exactly what has actually happened, why Mr Sombath has gone missing and who have been involved in the incident."
Authorities were "seriously investigating", it said.
Arbitrary arrests and detentions persist in Laos despite laws prohibiting them, the U.S. State Department said in its 2011 human rights report, and police and security force members sometimes abused prisoners.
"The Lao authorities should recognise that Sombath's years of development work have earned him important friends around the world, and that the clamour for his release is not going to go away," Adams said.
(Writing by Amy Sawitta Lefevre; Editing by Robert Birsel)