A militant forum as well as pro-ISIL social media accounts published three pictures on Monday, showing the execution of the men in orange jumpsuits.

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

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

According to local residents, the massacre was carried out on a large roundabout six kilometers (four miles) east of the city of Tikrit at around 3:30 pm (1230 GMT).

They said the roundabout is at an intersection for roads leading to Tikrit, Kirkuk, and the town of al-Alam.

The dead were reportedly members of an anti-ISIL group of Sunni tribal fighters known as the Knights of al-Alam, and the Takfiri terrorists captured them in Tikrit and al-Alam over a week ago.

The ISIL has been in control of Tikrit since the beginning of the militants’ major offensive in Iraq six months ago.

Earlier in December, tribal leaders said that the ISIL Takfiris abducted and killed 16 members of an Iraqi Sunni tribe, fighting the group in the western province of Anbar.

The ISIL terrorists control some parts of Syria and Iraq. They are engaged in crimes against humanity in the areas under their control. ISIL militants have terrorized and killed people of all communities, including Shias, Sunnis, Kurds, and Christians.