BAGHDAD: Iraqis should not carry out hurried or ad hoc exhumations of mass graves left by extremists, as this makes identifying victims more difficult, Human Rights Watch said Wednesday.

Dozens of mass graves have been discovered in areas retaken from ISIS, whose rule in Iraq and Syria has been marked by widespread atrocities including mass summary executions.

"The strong desire to exhume the remains of loved ones from (ISIS) mass graves is perfectly understandable, but hastily conducted exhumations seriously harm the chances of identifying the victims and preserving evidence," Lama Fakih, HRW's deputy Middle East director, said in a statement.

"While exhuming the remains of those killed at (Khasfa) may be difficult, authorities should do what they can to make sure that those who lost their loved ones there have access to justice," Fakih said, referring to a mass grave site south of Mosul.

HRW said that the Khasfa site -- a large sinkhole where ISIS reportedly shot victims and pushed them in for disposal -- could contain the bodies of hundreds of people executed by the extremists.

But ISIS has planted explosives at the site, which killed a journalist and three members of Iraqi paramilitary forces in February.

HRW called for Iraqi authorities to fence it off "for the protection of the mass grave and those in the area, until deminers can clear the site."

"If exhumation is possible, the process should be carried out under international standards," the rights group said.

ISIS overran large areas north and west of Baghdad in 2014, but Iraqi forces have since regained much of the territory they lost.

Iraqi forces launched a massive operation to retake Mosul in October, recapturing its eastern side before setting their sights on the smaller but more densely-populated west.

Paramilitary forces said earlier this month they had discovered another suspected mass grave at Badush prison, near Mosul.

ISIS reportedly killed up to 600 people after seizing Badush in 2014, and was also said to have held hundreds of kidnapped women from Iraq's Yazidi minority at the facility.