Eighteen men - 15 of them Iranian - were slain Friday by an armed group while they were working on a gas pipeline that runs from Iranian territory to a power plant in eastern Iraq, a source in the Iraqi security forces told Efe.
The assailants wounded seven other Iraqi and Iranian workers in the attack, then quickly disappeared as security forces arrived on the scene.
In another incident, four civilians died and another 13 were wounded by the explosion of a car bomb parked near a popular market in the city of Madain, just south of Baghdad.
A total of seven people died Friday and another 20 were injured in other attacks in Iraq, while police prevented a jailbreak by a score of inmates at a Baghdad prison.
Iraq is going through a resurgence of sectarian violence and terrorist attacks. During the month of November, 948 people, mostly civilians, were killed in the attacks, according to Iraqi government figures. EFE