Iran's top security official has denounced an assassination bid on Iraqi Prime Minister Mustafa al-Kadhimi, linking it to "foreign think tanks".

In a statement on Sunday, Ali Shamkhani, who heads the Supreme National Security Council (SNSC) of Iran, called the attack on Kadhimi a "sedition", which he said "must be traced back to foreign think tanks."

Kadhimi escaped unhurt after a drone laden with explosives targeted his house in Baghdad's highly-fortified Green Zone early on Sunday.

The attack followed violent unrest in the country over recent election results, which has created uncertainty over Kadhimi's stint in the top echelons of power.

Shamkhani, referring to unnamed "foreign think tanks", said they have brought "nothing but insecurity, discord and instability" to the people of Iraq "through creation and support of terrorist groups and occupation of this country for years."

Shamkhani, a former Islamic Revolutionary Guards Corps (IRGC) commander, has been a strong critic of the US presence in Iraq.

During his meeting with Kadhimi in Tehran in September, he said the two decades of US presence in Iraq had proven that it "bore nothing but the destabilization of the country's security and stability."

Iranian Foreign Ministry spokesman Saeed Khatibzadeh also condemned the assassination attempt, stressing Tehran's "continued support for stability, peace and security in Iraq."

No group has so far claimed responsibility for the attack on the Iraqi premier.

An official of the Iran-backed Kataib Hezbollah group dismissed reports that Iraqi groups were behind the attack on Kadhimi.

In a statement on Sunday, the US Department of State spokesperson Ned Price called it an "act of terrorism" that was "directed at the heart of the Iraqi state."/aa