"The incident took place last on Friday night, when IS militants using small boats docked near a group of fishermen at the edge of the lake, which located some 50 km north of the city of Fallujah, and shot the men dead before they blew their bodies up and set fire to their cars," the source said on condition of anonymity.

The victims turned out to be from the Shiite holy city of Najaf, some 160 km south of the Iraqi capital Baghdad, the source said, adding that the remnants of torn bodies were transferred to the main hospital of Fallujah, some 50 km west of Baghdad.

Tharthar Lake stretches over a vast area between the provinces of Anbar and the neighboring Salahudin. Many people from neighboring provinces used to fish in the Lake, which is fed by Tigris River through Samarra dam.

The lake and surrounding areas were once under control of the IS group when the extremist militants seized large swathes of Iraqi territories in June 2014.

The security situation in Iraq has been dramatically improved after Iraqi security forces declared they had fully defeated the extremist IS militants across the country late in 2017.

However, the extremist militants have since regrouped in urban, desert and rugged areas, carrying out guerilla attacks against security forces and civilians despite recurrent operations to hunt them down.