Bamako - Malian and Burkinabe soldiers have killed, tortured and disappeared civilians while trying to root out jihadists in central Mali, Human Rights Watch said on Friday.
"Mali and Burkina Faso military operations to counter the growing presence of Islamist armed groups in central Mali have resulted in serious human rights violations," a statement said.
"Since late 2016, Malian forces have committed extrajudicial killings, enforced disappearances, torture, and arbitrary arrests against men accused of supporting Islamist armed groups".
The violations occurred in the Mopti region, near the Burkinabe border, HRW said, between late 2016 and July 2017, and also in Segou, a few miles west.
HRW said three graves had been found that contained the remains of at least 14 men executed after being detained by Malian soldiers. The group also documented 27 cases of unexplained disappearances.
Witnesses described "being bound, severely beaten, and burned after soldiers held their heads close to the exhaust pipe of a military truck".
The rights group said Burkinabe soldiers detained some 70 men in June, accused of belonging to an armed Islamist group. The men were allegedly so severely beaten that two died in custody.
"The skewed logic of torturing, killing, and 'disappearing' people in the name of security only fuels Mali's growing cycle of violence and abuse," Corinne Dufka, the HRW Sahel director, said.
Dufka called on both governments to prosecute the offenders. There was no immediate reaction to the report from either country.
Islamist jihadists took over territory in northern Mali in 2012, but were driven out by a French-led military intervention in January 2013.
Mali and four neighbouring countries - Burkina Faso, Chad, Mauritania and Niger - are working to set up a counterterrorism force to fight jihadists in the Sahel, a region France has warned could become a haven for extremists.
In the latest attack to shake the region, gunmen opened fire on a restaurant in the Burkina Faso capital of Ouagadougou on August 14, killing 19 people including several foreigners.