Iraqi Prime Minister Adel Abdul-Mahdi has announced his resignation after the country's top Shia Muslim cleric called for politicians to reconsider their support for a government rocked by weeks of deadly anti-establishment unrest.

"In response to this call, and in order to facilitate it as quickly as possible, I will present to parliament a demand (to accept) my resignation from the leadership of the current government," a statement signed by Mr Abdul-Mahdi said.

The statement did not say when he would resign.

Parliament is to convene an emergency session on Sunday to discuss the crisis.

Grand Ayatollah Ali al-Sistani earlier urged parliament to considering withdrawing its support for Mr Abdul-Mahdi's government to stem spiralling violence.

Security forces, meanwhile, shot dead at least three people in the southern city of Nassiriya as clashes continued.

Iraqi forces have killed nearly 400 mostly young, unarmed demonstrators since mass anti-government protests broke out on 1 October. More than a dozen members of the security forces have also died in clashes.

The burning of Iran's consulate in the holy city of Najaf on Wednesday escalated violence and drew a brutal response from security forces who shot dead more than 60 people nationwide yesterday.

The unrest is Iraq's biggest crisis for years.

It pits protesters from Shia heartlands in Baghdad and the south against a corrupt Shia-dominated ruling elite seen as pawns of Iran.

Iraq's current political class is drawn mainly from powerful Shia politicians, clerics and paramilitary leaders, including many who lived in exile before a US-led invasion overthrew Sunni dictator Saddam Hussein in 2003.

Grand Ayatollah Sistani, who only weighs in on politics in times of crisis and wields huge influence over public opinion, warned against an explosion of civil strife and tyranny. He urged government forces to stop killing protests and protesters themselves to reject all violence.

The government "appears to have been unable to deal with the events of the past two months ... parliament, from which the current government emerged, must reconsider its choices and do what's in the interest of Iraq," his representative said in a televised sermon.


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Protesters "must not allow peaceful demonstrations to be turned into attacks on property or people," he said.

Wednesday's attack on the Iranian consulate in Najaf set off a sharp escalation of violence.

Yesterday, security forces shot dead 46 people in another southern city, Nassiriya, 18 in Najaf and four in Baghdad, bringing the death toll from weeks of unrest to at least 417, most of them unarmed protesters, according to a Reuters tally from medical and police sources.

Clashes between protesters and security forces broke out early today in Nassiriya killing three people and wounding several others, hospital sources said.

Iraq's "enemies and their apparatuses are trying to sow chaos and infighting to return the country to the age of dictatorship ... everyone must work together to thwart that opportunity," Grand Ayatollah Sistani said.