One of Iraq's main Shia militias has met Sunni clerics for talks after days of bloodshed following the destruction of the Shia shrine at Samarra.
At least a dozen people were killed in Baquba
Moqtada al-Sadr's militia and the Sunni Association of Muslim scholars vowed to help each other defend holy places.
US President George W Bush rang faction leaders backing a unity government and urging a common front against violence.
The move came after another day of attacks. At least 165 people have died in sectarian violence since Wednesday.
Attacks on Saturday left at least 36 people dead - 12 of them Shia family members gunned down in Baquba, north of Baghdad, officials said.
The bodies of 14 Iraqi commandos were also recovered in south Baghdad following a gun battle with Shia militiamen.
In other developments:
- A car bomb in the shrine city of Karbala kills eight
- Two die in an attack on the funeral of a prominent Iraqi journalist killed in the aftermath of the al-Askari shrine bombing
- Iraq's national security adviser disputes a US military report which says not a single Iraqi army battalion is able to fight the insurgency without US help
- A curfew is extended in Baghdad to try to quell the violence.
Civil war fear
The bombing of the al-Askari shrine in the city of Samarra, one of the country's holiest Shia sites, has led to fears that Iraq may descend into civil war.
The joint statement issued by Moqtada al-Sadr's militia and the Sunni clerics condemned the destruction of the shrine and its violent aftermath.
They agreed to look into the possibility of the Mahdi army being deployed to protect mosques and other sites of religious importance in Iraq.
BBC correspondents in Baghdad says the deal is fraught with potential difficulties because many of these sites are currently controlled by rival armed groups or the Iraqi armed forces.
It would also contravene an order announced by Iraqi Prime Minister Ibrahim Jaafari on Saturday that bans the carrying of weapons in public by anyone other than the official security forces.
Mr Jaafari and President Jalal Talabani were among senior Iraqi political leaders who met for talks on Saturday.
The Iraqi government has now extended until Monday morning a ban on cars in Baghdad.
The authorities had earlier renewed a curfew covering Baghdad and the provinces of Diyala, Babil and Salahuddine.
Defence Minister Saadoun al-Dulaimi called for Iraqis to unite against extremists, saying no one would benefit from civil war.
Plea for calm
Despite measures taken by the authorities, violence broke out on Saturday at the funeral of Atwar Bahjat, a prominent Iraqi journalist.
Bahjat and her crew were attacked and killed while reporting
The funeral procession came under fire as it was approaching the cemetery, and then was bombed as it returned after the burial.
At least two people are reported to have died in the blast, and five more were injured, some seriously.
Ms Bahjat and two crew members from al-Arabiya TV were killed in the wake of the attack on the al-Askari shrine.
In Karbala, a predominantly Shia market city which is not under curfew, at least eight were killed and 30 injured in a car bombing.
The centre of Baghdad was calm, with streets virtually empty for a second day and no newspapers published.