BAGHDAD - Iraqi anti-government protesters clashed with security forces on Sunday, leaving three dead and dozens wounded as a rights group warned a deadly crackdown could spiral into a "bloodbath".

Mass rallies calling for an overhaul of the ruling system have rocked the capital Baghdad and the Shiite-majority south since October 1, but political forces closed ranks this week to defend the government.

The consensus among the elite seems to have paved the way for a crackdown.

On Sunday evening, three protesters were shot dead by security forces in the southern city of Nasiriyah, while dozens of demonstrators were wounded in Baghdad.

The three deaths bring the toll to 15 protesters killed since Saturday, after nine were killed in Baghdad and three in the southern city of Basra when security forces cleared out protest sites.

Despite the violence, demonstrators tried to regroup on Sunday in Baghdad's main protest camp at Tahrir Square, while hundreds of others dug in at the nearby Khallani square.

"Since last night, security forces have been trying to advance into Tahrir to empty it," said a protester draped in an Iraqi flag.

Protesters could be seen trying to bring down large concrete walls that security forces had erected to cut off Tahrir from Khallani.

Smoke from tear gas covered Khallani as protesters ran for cover while ambulances and tuk-tuks zipped across the square to evacuate the wounded.

"For 16 years the authorities have done nothing for us and now they are killing us in cold-blood," shouted a protester.

A medical source said around 30 people were wounded on Sunday in Khallani.

"This is turning into nothing short of a bloodbath," said Amnesty International.

"All government promises of reforms or investigations ring hollow while security forces continue to shoot and kill protesters," said Amnesty's regional director Heba Morayef.

In the first official toll in days, parliament's human rights committee said 319 people had been killed since protests first erupted, including demonstrators and security forces.

The committee said snipers were active near protest sites and hunting rifles were used against demonstrators as well.

Warning that a "climate of fear has set in", the United Nations mission in Iraq UNAMI proposed a series of steps to end the crisis.

It called for "maximum restraint in the handling of the protests, including no use of live ammunition, ban the improper use of non-lethal devices (such as tear gas canisters)".

UNAMI urged the release of demonstrators and called for an investigation into the abductions of activists and doctors, who rights group say have been taken by security forces or armed groups.

It proposed a raft of measures to be undertaken over the next weeks and months, including implementing electoral and constitutional reforms, prosecuting those involved in corruption and enacting laws to prevent graft. -AFP