Rights groups in Thailand have urged the government to investigate the apparent enforced disappearance of Od Sayavong, a prominent pro-democracy activist from Laos who has been missing for almost two weeks.

The 34-year-old Laotian activist was last seen at his Bangkok home on 26 August, sparking fears for his safety in a region where there has been a spate of enforced disappearances of political activists.

“The Thai government should immediately provide information on the whereabouts of outspoken Lao activist Od Sayavong,” said Brad Adams, the Asia director at Human Rights Watch. “Bangkok’s streets should be safe from abductions and wrongful arrests.”

The pro-democracy campaigner had been living in Thailand as he sought resettlement to a third country by a UN refugee agency and was connected to the Free Lao group, a network of migrant workers and activists living in exile in Bangkok, who held occasional protests and peacefully advocated for human rights and democracy in Laos.

Several members of the network recently told HRW they had been put under surveillance and intimidated by Thai and Lao authorities.

Colleagues of the Laotian activist filed a report with the Thai police on 2 September but no progress in the investigation has been reported.

On Friday, a defence ministry spokesman, Lt Gen Kongcheep Tantravanich, denied knowledge of Od’s whereabouts.

The one-party communist Lao government has arbitrarily arrested and detained critics before, while the Thai government has collaborated with foreign governments to arrest and forcibly return exiled dissidents.

The disappearance of Od Sayavong follows a series of similar cases in recent years, including that of five Thai activists who have disappeared from their homes in Laos since 2016. In December two of their bodes were found in the Mekong River, their stomachs pumped with concrete.

The disappearance of Od Sayavong comes days after the charred remains of ethnic Karen leader Por Cha Lee Rakcharoen, or “Billy”, were found in an oil drum and lake in a Thai national park, five years after he went missing.

Rights groups say 30 human rights activists have disappeared or been murdered in Thailand since 2001.