"I'm doing fine, praise be to God, and I call for calm and restraint on the part of everyone for the good of Iraq," Kadhemi wrote on Twitter, after what his office called a "failed assassination attempt".

Two security sources earlier confirmed the attack in the heavily-guarded Green Zone, which also hosts the US embassy and is frequently targeted by rocket attacks.

A large number of security forces were deployed in and around the Zone following the attack, according to a security source.

The attack came amid soaring political tensions over the results of October 10 elections.

Preliminary results of that poll saw the Conquest (Fatah) Alliance, the political arm of the pro-Iran multi-party Hashed al-Shaabi paramilitary network, suffer a substantial decline in its parliamentary seats. The group's supporters have denounced the outcome as "fraud".

Hundreds of Hashed supporters clashed with police on Friday while protesting near the Green Zone to vent their fury over the election result.

One protestor died of their injuries in hospital, according to a security source, while a Hashed source said two demonstrators were killed.

The health ministry reported 125 injuries, most of them from the security forces.

Several hundred supporters of pro-Iranian groups returned to the Green Zone on Saturday to protest.

Some burned a portrait of the prime minister, whom they called a "criminal".

According to preliminary tallies, the Conquest won around 15 of the 329 seats in parliament last month, down from 48 it held previously, which made it the second-largest bloc.

The big winner this time, with more than 70 seats according to the initial count, was the movement of Moqtada Sadr, a Shiite Muslim preacher who campaigned as a nationalist and critic of Iran.

Final election results are expected within weeks.