Iraqi troops have found a mass grave in the western city of Ramadi containing the bodies of 40 men believed to have been executed by the Islamic State group, officials said Friday.

It is the latest of dozens of such grisly finds made by Iraqi forces since they drove the jihadists out of the swathes of northern and western Iraq that they occupied in 2014.

Ammar Nuri al-Dulaimi, an official from a Martyrs Committee for Anbar province, said the bodies had bullet wounds to the head, suggesting they were executed by IS.

An army colonel, who asked not to be named, said troops had uncovered the mass grave during a sweep of the Al-Tach neighbourhood in the south of Ramadi, capital of the province.

The army retook the city in December 2015.