Ibrahim al-Jaafari, the Shia prime minister, flanked by Kurdish and Arab Sunni leaders, called on Iraqis on Saturday to unite and fight terrorism in a news conference carried live to the nation on state television.
With the gravest crisis since the US invasion threatening his plan to withdraw 136,000 troops, George Bush, the US president, made calls to Iraqi leaders on all sides urging them to work together to break a round of attacks sparked by the suspected al-Qaida bombing of a Shia shrine on Wednesday.
Those top leaders then met for talks directed at getting plans for a national unity government back on track.
Film of the meeting, attended by the US envoy, was broadcast live on state television in a clear effort to defuse sectarian tensions.
The White House announced after Bush's calls to Baghdad that: "He [Bush] encouraged them to continue to work together to thwart the efforts of the perpetrators of the violence to sow discord."
"If there is a civil war in this country it will never end"
Iraqi Defence Minister
Zalmay Khalilzad, the US ambassador, who has been criticised by Shia leaders this week for pushing to have Sunnis brought into government, said a unity government would help to avert the risk of civil war, a risk, he said, that had diminished on Saturday.
"There is still a danger," he said. "But the risk of going to war because of the ... bombing has diminished."
In a lengthy interview on Iraqi state television, he assured Iraqis that Washington was ready to help in any way: "The United States has a lot invested in Iraq. Iraq's failures are ours."
Earlier, aides to Shia cleric Muqtada al-Sadr met Sunni religious and political leaders to try to halt four days of bloodshed and made joint calls for Muslim unity.
Al-Sadr denies his black-clad al-Mahdi Army militiamen have been involved in attacks on Sunni mosques.
Two Iraqi Sunnis from Baghdad, meanwhile, told Aljazeera.net about the lawlessness sweeping the Iraqi capital.
Umar al-Umari, an employee at the Ministry of Transportation, said armed men were storming Sunni houses and killing everybody inside.
Police said three Sunni mosques
were attacked overnight
"It's a sectarian cleansing. They are breaking into Sunni houses and killing everybody inside. No government or US forces are seen in the area."
Another Iraqi citizen, who preferred to remain anonymous, said that his uncle, cousin and nephew were killed on Thursday, while praying in Ahmad Rauf mosque.
"My uncle, his son and my nephew were killed while praying just because they were Sunnis."
Also on Saturday, Sadun al-Dulaimi, the Iraqi defence minister warned of the risk of an endless "civil war" as sectarian violence flared again, killing more than 40.
"If there is a civil war in this country it will never end," he said on Saturday as a traffic ban around the capital was extended to Monday after attacks on Sunni mosques and car bomb in a Shia holy city.
"We are ready to fill the streets with armoured vehicles."
Al-Dulaimi called for calm, saying 119 people had been killed since the bombing of the Golden shrine in Samarra at dawn on Wednesday.
Tallies of reports from police suggest the toll is at least twice that, including more than 40 on Saturday.
Police in the capital said they found the bodies of 14 police commandos near one of three Sunni mosques that police said were attacked overnight by armed men wearing black.
A car bomb killed eight people and wounded 31 at a market in the Shia city of Karbala, south of Baghdad.
Near Baquba, police said assailants killed 12 members of one family in what they said was a sectarian attack on Shia.
Mortars fell on Shia al-Sadr City in Baghdad, killing three people in one house, an al-Sadr aide said.
"The United States has a lot invested in Iraq. Iraq's failures are ours"
Three others were killed in north Baghdad by a mortar apparently aimed at a Sunni mosque.
Three security men were killed in separate gun and bomb attacks on the funeral cortege in western Baghdad of an Iraqi journalist killed as she reported in Samarra on Wednesday.
Rival Shia leaders deny sending militias against Sunni targets; but shows of force strengthen them in negotiations.
Iraqi and US officials blamed the bloodless but symbolic attack on Samarra's Golden Mosque on al-Qaida, saying it wanted to wreck the project for democracy in Iraq; al-Qaida accused Shia of carrying it out as an excuse for attacks on Sunnis.
Abroad, there has been concern that Iraqi sectarian violence could inflame the entire Middle East if it got out of hand.