Tribal leaders in Iraq are warning of war unless the country splits into a federation amid a deadly new wave of apparently sectarian violence.

Monday's attacks across Iraqi cities left at least 77 people dead and more than 248 others injured, officials say, pushing the death toll over the past week to well above 200.

On the same day, the pan-Arab newspaper Al-Hayat reported that Sunni protest leaders had called for "armed confrontation or the declaration of an [autonomous] region".

In response, Nouri al-Maliki, the Iraqi prime minister, said he was willing to contemplate the establishment of an autonomous region in the Sunni-dominated western provinces, provided it came about through the correct legal procedures, according to the independent Al Sumaria television.

Maliki also said he would overhaul Iraq's security strategy. "We are about to make changes in the high and middle positions of those responsible for security, and the security strategy," he said at a news conference in Baghdad on Monday.

"We will discuss this matter in the cabinet session tomorrow [Tuesday] to take decisions," he said, without providing further details.

"I assure the Iraqi people that they [attackers] will not be able to return us to the sectarian conflict" that killed tens of thousands of people in Iraq in past years.

Sectarian violence

Weeks of sectarian violence have stirred fears of a return to all-out civil war, and Monday's bloodshed is likely to heighten them further.

In Hilla, south of Baghdad, bombings during evening prayers at two Shia Muslim mosques killed 13 people and wounded another 71, police and a doctor said.

One bomb exploded inside Al-Wardiyah mosque, while a suicide bomber detonated an explosives-rigged belt at Al-Graita mosque nearby.

A car bomb exploded in Shaab, a mainly Shia area in north Baghdad, killing 12 people and wounding at least 20, officials said.

Two car bombs went off in the main southern port city of Basra, killing 13 people and wounding 48, while a wave of other bombings hit Baghdad, killing at least 11 people and wounding 102.

In Balad, north of the capital, a car bomb exploded near a bus carrying Iranian pilgrims, killing eight people and wounding another 15.

North of Baghdad, six Sahwa (Awakening) anti-al-Qaeda fighters were killed and 27 wounded in three separate attacks on Monday.

The Sahwa are made up of Sunni Arab tribesmen who joined forces with the US military against al-Qaeda from late 2006, helping to turn the tide against the insurgency.

And a car bomb killed one person and wounded four in Rutba, a town in Anbar province, west of Baghdad, while a roadside bomb in the northern city of Mosul wounded three people.

Police officers killed

Monday's violence across Iraq came after 24 police were killed overnight, again in Anbar.

Police Lieutenant-Colonel Majid al-Jlaybawi said police and soldiers carried out a joint raid to free kidnapped police officers, but clashes ensued.

Twelve kidnapped policemen were killed and four wounded, although it was not immediately clear if they were caught in crossfire, killed by their abductors, or a combination of the two.

Mohammed Hadi, one of the wounded policemen, told AFP news agency they had been abducted on the highway between Baghdad and Jordan on Saturday.

In Haditha, a town in Anbar, armed men attacked a police station, killing eight police, among them two officers, officials said.

And assailants killed four police and wounded three in an attack on another police station in the town of Rawa, also in Anbar.

A shop owner was killed in Mosul on Sunday.

Emergency session called

Against this backdrop, Osama al-Nujaifi, Iraq's Sunni parliamentary speaker, has called an emergency session on Tuesday to discuss the worsening security situation.

Al-Nujaifi, who asked security chiefs on Saturday to attend the session, has also demanded "a clear position from the international community on what is taking place in Iraq".

His decision drew criticism from Maliki, who urged politicians to stay away from the parliamentary session.

"The politicians bear the responsibility for the sectarian escalation because of their statements, calls for violence and sectarian positions," Maliki said.

"Ignorant people pick up on that and go out bearing weapons and calling for fighting."

Furthermore, accusing some politicians of having set up armed groups, Maliki said: "The Chamber of Deputies is one of the main players in the current disturbances in the country."