By Osman Shalash

BAGHDAD

At least five Shia militiamen were killed and dozens injured Tuesday by a suicide bombing in northern Iraq, according to an Iraqi police officer.

Lieutenant-Colonel Iyad Abdel-Khaliq said a bomber detonated his vehicle near an office of the Hashd al-Shaabi, an umbrella group of Iraqi Shia militias, in the town of Al-Dor in the northern Saladin province.

"At least five militiamen were killed and another 35 injured in the attack," Abdel-Khaliq told Anadolu Agency.

Iraqi police imposed a curfew on the town following the attack, for which no group has yet claimed responsibility.

The Hashd al-Shaabi is currently taking part in an army-led military offensive launched last month aimed at retaking territory captured in 2014 by the Daesh terrorist group.

The Shia militia group has previously been accused of committing human rights abuses while retaking territory from Daesh.

On Sunday, an Iraqi tribal leader accused the Hashd al-Shaabi of executing 50 Sunni prisoners in northern Iraq.

"Roughly 50 Sunni prisoners were executed by the Hashd al-Shaabi militia inside the Amerli prison [in Saladin province]," Thaer al-Bayati told Anadolu Agency.

He said the executions were ostensibly carried out in revenge for the death of a senior police officer in clashes with Daesh militants near Amerli last week.

Last month, video footage was widely shared on social media showing a Shia militiaman mistreating civilians fleeing the city of Fallujah, which was captured by Daesh in early 2014.

After a one-month campaign, the Iraqi army managed to retake the western city from Daesh last week.

The Iraqi authorities also say they are investigating reports that 17 civilians were executed by Shia militiamen during the campaign to capture Fallujah.

Iraq has suffered from a devastating security vacuum since mid-2014, when Daesh overran the northern and western parts of the country.

*Anadolu Agency correspondent Mohamed Sabry contributed to this report from Egypt