Thai authorities have forced a human rights group to cancel the launch of its report on the Vietnamese government's persecution of an ethnic minority.

The 33-page report by Human Rights Watch describes persecution of Montagnard Christians in Vietnam's Central Highlands, whose religious practices have been described by the government as "evil."

Thai police said in a statement Friday the scheduled event at the Foreign Correspondents Club of Thailand could impact national security or the relations between Thailand and Vietnam.

Human Rights Watch researcher Sunai Phasuk said the intervention will damage Thailand's already tarnished international reputation under the military rule.

Thai authorities have cracked down on critics and dissents since last May's coup.

Friday's press conference was the third event in one month that has been cancelled at the venue.