“A group of Daesh fighters came from the Hamrin Mountains, crossed the Tigris River after midnight and attacked the checkpoint at the entrance to the village of Albu Juwari, north of Baiji,” a police official, speaking on condition of anonymity, said on Saturday.

He added that five members of the family were killed in the assault, while a sixth is in a critical condition.

All were members of a tribal force operating under the umbrella of the Popular Mobilization Units – better known by the Arabic name Hashd al-Sha’abi.

Meanwhile, an unnamed senior Iraqi security source told Arabic-language Baghdad Today news agency that the Iraqi Federal Police had arrested a high-profile Daesh militant commander as he was trying to flee to the country’s northern semi-autonomous Kurdistan region.

The source said Mohammed Khalaf al-Jabouri was captured at a checkpoint between Makhmur town and the major Kurdish city of Erbil, which is located approximately 350 kilometers north of the capital Baghdad.

Separately, Abdul Sattar al-Biraqdar, spokesman for Iraq's Supreme Judicial Council, said in a statement on Thursday that a Baghdad court had sentenced two Iraqi nationals to death and another to life imprisonment over their membership in Daesh and involvement in acts of terrorism.

The trio confessed to having fought against security and military forces in Nineveh and Anbar provinces. They then fled to Syria after the two provinces were liberated, before being arrested by Syrian forces and turned over to Iraqi officials.