Suspected Boko Haram fighters have been "brutally tortured" by security forces in Cameroon, a rights group says.
Amnesty International said in a report that the suspects, including women and children, were beaten, water-boarded and forced into stress positions.
The cases allegedly happened between 2013 and 2017, and dozens of detainees died as a result, it added.
Cameroon has denied the allegations, saying Amnesty was being used as a Boko Haram "propaganda tool".
Information Minister Issa Tchiroma Bakary told the BBC that the security forces were "fighting to protect the physical integrity" of Cameroon and there was "no need for our army to kill innocent civilians".
Boko Haram frequently carries out attacks in the country.
The Islamist group, based in neighbouring Nigeria, has killed more than 1,500 civilians in Cameroon since 2014, and abducted many others, Amnesty said.
Victims described a least 24 methods of torture at more than 20 different sites, the report said.
In one of those places, it said, there was the presence of US and French military personnel. There was no evidence that foreign forces were involved, but Amnesty urged both countries to investigate the allegations.
The report added that people suspected of supporting the militants were often being detained without evidence.
- Founded in 2002 in Nigeria, initially focused on opposing Western-style education. Boko Haram means "Western education is forbidden" in the Hausa language
- Launched military operations in 2009
- Thousands killed, mostly in north-eastern Nigeria, hundreds abducted
- Joined so-called Islamic State, now calls itself IS's "West African province"
- Seized large area in north-east Nigeria, where it declared caliphate
- Regional force has now retaken most of the captured territory