Baghdad, Dec 16 (IANS): New photos have been uploaded on social network sites, showing mass execution of 13 men by Islamic State (IS) militants in Iraq.

A militant forum as well as pro-IS social media accounts published three pictures Monday, showing the execution of the men clad in orange jumpsuits, Press TV reported Tuesday.

In the first picture, 11 men could be seen kneeling, with one black-clad and masked gunman behind each one.

In the second photo, the gunmen wave their handguns after the execution and in the third, a small gathering of people, including children, can be seen near the 13 bodies.

According to local residents, the massacre was carried out some six km from Tikrit city.

The victims were members of an anti-IS group of Sunni tribal fighters known as the Knights of Al-Alam, and the IS terrorists captured them in Tikrit over a week ago.

The IS has been controlling Tikrit since the beginning of the militants' major offensive in Iraq six months ago.