Iraqi security officials and militia sources said the drone attack that targeted the residence of Iraqi Prime Minister Mustafa Al-Kadhimi on Sunday was carried out by at least one Iran-backed militia, Reuters reported.
The sources said it was unlikely that Tehran had approved the attack, because it is keen to avoid an escalation of violence on its western border.
Al-Kadhimi escaped unharmed from the attack on his residence in Baghdad, carried out by three drones loaded with explosives, while several of his bodyguards were injured.
The incident exacerbated tensions in Iraq, where powerful pro-Iran armed factions questioned the results of last month's general elections, in which they suffered a crushing defeat which significantly reduced their power in parliament.
No group has claimed responsibility for the attack. The Iranian government also did not respond to a Reuters' request for comment.
An Iraqi security official said the drones used in the attack are similar to the Iranian-made drones and explosives used this year in attacks on US forces in Iraq.