BAGHDAD, Iraq — Friends and relatives of Shiite Muslims killed in a mosque attack carried their coffins through the streets of several Baghdad neighborhoods today, chanting religious rites and beating their heads and chests.

An Iraqi flag covered one of the coffins, a symbol of unity at a time of escalating sectarian strife.

"We are the sons of one country, and one religion," Jabar al-Maliki, an elderly cleric in white robes, said at one of the funeral processions in Sadr City. "These criminal acts are conducted by corrupt, terrorist groups that ... have no sense of humanity."

At least 79 people were killed and more than 160 wounded in Friday's attack, the deadliest in Iraq this year. Suicide bombers, one wearing women's robes, set off their explosives as worshippers left the Buratha mosque in northern Baghdad after the main weekly religious service.

The horrific explosions are likely to stoke tensions between Shiite and Sunni Muslims, making it even harder for them to form a government that represents all Iraqis. The United States sees such a government as crucial to stemming the violence, but negotiations have stalled over Sunni and Kurdish opposition to Prime Minister Ibrahim al-Jaafari, the Shiite candidate to lead the government. Al-Jaafari has refused to step aside, and his Shiite coalition has been reluctant to reconsider his nomination for fear of splintering the alliance.

Police said there were two suicide bombings at the mosque, and an Associated Press photographer saw evidence of two blasts — one at the outer wall surrounding the compound and another at the entrance to the mosque building.

But Jalal Eddin al-Sagheer, the preacher at the mosque and one of the country's leading politicians, said there were three bombings.

Mainstream Sunni Arab politicians condemned the bombings, calling on all religious and political leaders to come together in the interest of national unity.

Police Lt. Col. Falah al-Mohammedawi, who gave the casualty figures, said one of the suicide attackers wore a black abaya, the full-length robe worn by devout Muslim women.

He allowed for the possibility the attacker was a man dressed in women's clothes to conceal explosions. At the compound's entrance, the AP photographer saw a leg and most of the head of what appeared to be one of the bombers. The head had long hair and the leg was thin, and the photographer thought it was the remains of a woman.

The attack on the mosque was the second in as many days against a Shiite religious site. On Thursday, a car bomb exploded about 300 yards from the Imam Ali mosque in Najaf, killing 10 people. Najaf, 100 miles south of Baghdad, is the most sacred city in Iraq for Shiite Muslims.

Also Friday, the U.S. military reported the deaths of four more American service members, including one who died from wounds suffered in Baghdad. Two Marines and a soldier were killed Thursday.