Cameroonian security forces have arbitrarily arrested, beaten or threatened at least 24 people since February under a law that criminalises same-sex relations, Human Rights Watch said Wednesday.
"These recent arrests and abuses raise serious concerns about a new upsurge in anti-LGBT persecution in Cameroon," the HRW's Neela Ghoshal said in a statement.
"The law criminalising same-sex conduct puts LGBT people at a heightened risk of being mistreated, tortured, and assaulted without any consequences for the abusers," wrote Ghoshal, associate director of HRW's gay rights programme.
Police conducted a raid on February 24 on the offices of HIV/AIDS prevention and treatment group Colibri in the western town of Baffoussam and arrested 13 people including seven staff, HRW said.
They were accused of homosexuality, and released on February 26 and 27, it said.
"Police told us we are devils, not humans, not normal. They beat a trans woman in the face, slapped her twice in front of me," a 22-year-old transgender woman was quoted as saying.
The police also forced a 26-year-old transgender woman to undergo an HIV test and an anal exam, HRW said.
"The doctor was embarrassed but said he had to do the examination because the prosecutor needed it... It was the most humiliating thing I've ever experienced," she told HRW.
The anti-gay law in the central African country carries jail terms of six months to five years and fines of up to 200,000 CFA francs ($360) for same-sex relations.
Such arrests had decreased in recent years but appear to be rising again.
The Cameroonian authorities did not immediately reply when contacted by AFP.