Kadhemi escaped unhurt from the November 7 assassination bid, in an attack that has gone unclaimed.

Explosive-packed drones were used in the assault, with one hitting his Baghdad residence while a second one failed to explode and was found on the roof of the house.

A bomb disposal team and forensic experts were tasked with examining the second drone to lift any possible fingerprints, national security advisor Qassem al-Araji told a news conference.

The teams were then expected to blow up the drone but later revealed they had failed to lift any fingerprints beforehand, Araji said.

As a result, a committee investigating the attack decided to arrest the eight officers, including two generals, Araji said.

A probe into why they failed to carry out their instructions has been launched, he added.

The commission "does not want to accuse anyone or any faction", Araji said. "But what happened indicates there has been negligence."

The attack came two days after two people were killed as security forces clashed with supporters of Iran-backed parties that lost ground in Iraq's October 10 elections.

The violence broke out as demonstrators tried to break into the high-security Green Zone which houses government buildings and foreign embassies.