The United States called Monday for an investigation into the death of a Tanzanian opposition figure killed over the weekend after his party said he was beaten and doused in acid.

The killing of Ali Mohamed Kibao comes a month after other leading members of his opposition party, CHADEMA, were briefly detained in a mass roundup that raised concerns about political repression returning to Tanzania.

Kibao, a retired military intelligence officer, was forced off a bus at gunpoint on Friday by suspected security agents as he was travelling to the northern port city of Tanga, party officials said.

His body was found in the commercial capital Dar es Salaam on Saturday.

The US embassy in Tanzania urged authorities to conduct an “independent, transparent, and prompt investigation” into the death.

“Murder and disappearances, as well as last month’s detentions, beatings, and other efforts to disenfranchise citizens ahead of elections, should have no place in a democracy,” the US embassy said in a post on X.

Tanzania is due to hold local elections in November and general elections late next year.

President Samia Suluhu Hassan has appeared to reverse some of the authoritarian policies of her predecessor John Magufuli, who died suddenly in March 2021, relaxing restrictions on opposition rallies and media.

But rights groups fear recent crackdowns suggest she is returning Tanzania to the repression of the Magufuli era.

Hassan called for a thorough probe into Kibao’s murder, calling it an “extremely grave incident”, and police say they are investigating.

Attending Kibao’s funeral on Monday in Tanga, Home Affairs Minister Hamad Masauni expressed his condolences, saying: “We cannot let this go unchecked”.