Sheik Mahmud al-Sumaidaei, a leading Sunni cleric in the Association of Muslim Scholars (AMS), criticised groups targeting civilians. He called for Iraq's religious and ethnic groups to take a stand against further bloodshed.
"I call for a meeting ... of all the country's religious and political leaders to take a stand against the bloodshed," al-Sumaidaei said during his sermon at Baghdad's Um al Qura Sunni mosque.
"We don't need others to come across the border and kill us in the name of defending us," he declared, a reference to foreign fighters who have joined the insurgency under the banner of al-Qaida. "We reject the killing of any Iraqi."
In Tuz Khormato, 209km north of Baghdad and site of one of the worst attacks, authorities said the attacker detonated his explosives-laden car as worshippers flowed out of the Hussainiyat al-Rasoul al-Azam mosque, a Shia Turkmen place of worship.
Police said 12 people were killed and 23 wounded in the bombing, which also destroyed 10 shops and eight cars.
"We were stepping out of the mosque and suddenly a big blast shook the ground," said Mustafa Ali, a 63-year-old ethnic Turkmen who escaped injury.
More than 200 people have been
killed in the past three days
"I saw many people scattered on the ground, drenched in their own blood. I wanted to ask the bomber, 'Why did you attack those innocents who had prayed?"' he said.
Police Captain Mohammed Ahmed said his men exchanged gunfire with another bomber before capturing him as he fled toward a second mosque. The man, who appeared to be in his early 20s, said he was from Saudi Arabia.
Friday's bloodshed began early, when armed men riding in a minibus opened fire on day labourers in an east Baghdad's al-Jadida district. Three workers died and a dozen were wounded in the drive-by attack.
In Hasswa, 48km south of Baghdad, a car bomb exploded near an Iraqi police patrol, killing three officers and wounding four, said police Captain Muthana Khalid. Unidentified assailants also stormed the house of the mayor in nearby Iskandariyah, killing him and four bodyguards.
Sheik Fadil al-Lami, the Shia cleric at Baghdad's Imam Ali mosque, was gunned down as he waited to gas up his car, said police Colonel Shakir Wadi.
Authorities also found the bodies of three people in the same part of the city, including one Iraqi soldier.
US marine killed
On Friday, the US military announced that a marine was killed near Ramadi, 110km west of Baghdad.
The soldier from the 2nd Marine Division was killed "from an indirect fire explosion" on Thursday, it said, using the normal term for a mortar attack.
Al-Zarqawi warned Shia and
Sunnis ahead of the referendum
The death brings to at least 1897 the number of American military personnel killed in Iraq since the US-led invasion of March 2003, according to Pentagon figures.
Major urban areas of Iraq have witnessed a surge in attacks against Iraqi security forces, US military targets, and civilians since al-Qaida in Iraq leader Abu Musab al-Zarqawi declared all-out war against the Iraqi Shia community.
In an audio tape recording that has not yet been authenticated, al-Zarqawi said all Iraqis working with US forces and/or supporting the government of Prime Minister Ibrahim al-Jaafari would now become targets.
He also warned the Sunni community not to participate in an upcoming referendum vote.
Shia, Sunni condemnation
As Shia and Sunni clerics condemned the rash of attacks, they also lashed out at the US-backed Iraqi government and US forces, holding them responsible for the recent violence because they were unable to improve security in the country two-and-a-half years after the US-led invasion that toppled Saddam Hussein.
Sunni and Shia clerics blame the
US presence for the violence
More than 300 followers of the influential Shia cleric Muqtada al-Sadr travelled from Baghdad's Sadr City to the Kathimiyah neighbourhood, where attacks on Wednesday killed 160 people, among them day labourers assembled to find jobs.
The Iraqi government was "responsible for the security deterioration, and (we say to them) if they cannot protect Iraqis, then let Iraqis protect themselves," Hazem al-Araji, a senior al-Sadr aide, told The Associated Press.
Sheik Abdul-Zahraa al-Suwaidi, also a Shia, said the violence had tarnished the image of Islam and Muslims, but he blamed the continued presence of 140,000 US troops for fuelling sectarian tension.
"You have to know that Iraq will gain its security if the occupation troops leave this country," al-Suwaidi told worshippers in Baghdad's Risafaa district.
At the United Nations, Iraqi Foreign Minister Hoshyar Zebari said he believes Iraq's government is capable of containing the violence.
"There is no complete immunity against terrorist attacks or suicide bombers or people who are ready to blow up ... car bombs or themselves and downtown markets or schools or to kill children," he said.