An Iraqi commanding officer and four soldiers lost their lives while five others sustained injuries in an assault believed to be carried out by Islamic State militants on an army post in eastern Iraq, two security sources said.

The attack took place in a rural area situated between Diyala and Salahuddin provinces, known to be a persistent hotspot for militant activity, even years after Iraq declared final triumph over the extremist group in 2017.

Iraq's ministry of defence said that an officer and several members of his regiment were killed "while thwarting a terrorist attack".

"Daesh terrorists launched an attack" on an army post in the village of Mtebija "killing four soldiers and the regiment commander," said a security source, using an alternate name for the Islamic State group.

Security forces repelled the attack but there were many casualties in the process, the statement added.

Iraq has seen relative security stability in recent years after the chaos of the 2003-U.S.-led invasion and years of bloody sectarian conflict that followed.

In 2014, the jihadist group seized significant territories in Iraq and neighbouring Syria, establishing its so-called "caliphate" and instigating a period of widespread terror. Iraqi forces, supported by a US-led military coalition, managed to defeat the group in Iraq by 2017 and in 2019, US-backed Kurdish forces reclaimed the last remaining territory held by the group in Syria.

But its remnants continue to carry out deadly hit-and-run attacks and ambushes, particularly from remote areas and desert hideouts.

In a report published in January, the United Nations said IS has "between 3,000 and 5,000 fighters" across Iraq and Syria.

Image source: AP