Gunmen have killed 18 engineers and workers near the northeastern town of Muqdayia in the Diyala province of Iraq on 13 December.
Among the dead were 15 Iranians and two Iraqis, who were killed by masked gunmen on their way back from working near the Naft Khana oil field at 7pm, according to local media reports.
The men had been working on a pipeline that will transport natural gas from Iran to power stations in Iraq when completed. They were all employed by an unnamed Iranian oil firm.
The 225-kilometre, 48-inch pipeline runs from Iran to the Mansuriya power plant in the eastern Diyala province, and then on to the Quds and Sadr power plants in Baghdad, which provide 2,500MW of electricity. It had been expected to be operational in November, supplying about 850 million cubic feet a day (cf/d) of gas.