A car bomb exploded outside a Sunni Muslim mosque Friday in Baghdad, killing at least eight people, officials said. Masked gunmen appeared at the scene later, firing randomly at people near the blast-damaged building.

An Associated Press photographer saw at least two bystanders gunned down by the masked men, one of whom held a pistol to the head of a woman.

A Sunni cleric also was abducted from his home in the capital by armed men wearing Interior Ministry police uniforms, his relatives said.

It was the latest kidnapping of a Sunni Arab by men wearing uniforms of the security forces, amid rising claims by the once-dominant minority that Shiite-led Interior Ministry forces and militiamen are targeting them in a widening campaign of sectarian violence.

The U.S. military announced that two American Marines were killed Thursday after their patrol was hit by a roadside bomb near Fallujah, 40 miles west of Baghdad. At least 2,269 U.S. military personnel have died since the Iraq war began in March 2003, according to an Associated Press count.

U.S. officials were analyzing a new videotape aired late Thursday by a Kuwaiti television station showing American journalist Jill Carroll, who appealed to supporters to do whatever necessary to secure her freedom.

The 22-second tape, aired by the private station Al-Rai, was the third showing the 28-year-old freelance reporter for The Christian Science Monitor since her Jan. 7 kidnapping in Baghdad by a group called the "Revenge Brigades."

She was wearing an Islamic headscarf and appealed in a calm, composed voice for her supporters to do whatever it takes to win her release "as quickly as possible." Her demeanor was vastly different to the previous tape aired Jan. 30 that showed her weeping.

Her abductors had threatened to kill her in the first video aired Jan. 17 if all female prisoners in Iraq weren't released. Five Iraqi women already have been freed, but Iraqi and U.S. officials said their releases were routine and not part of a swap for Carroll.

In political developments, Iraq's election chief, Adil al-Lami, started the clock Friday on the long-awaited formation of a new government, announcing final certified results for the country's Dec. 15 parliamentary polls.

The announcement confirmed initial results released last month, meaning the new 275-seat parliament, the first post-Saddam Hussein assembly with a four-year mandate, must convene within two weeks.

Intense negotiations are under way to form a national unity government, which will be dominated by a Shiite alliance that won 128 seats, and Kurds, who claimed 53. The U.S. hopes the Shiites and Kurds will welcome Sunni Arabs into powerful positions.

Two Sunni Arab blocs won a combined 55 seats, marking a threefold increase on the outgoing parliament. Sunni Arabs form the backbone of the raging insurgency, and bringing them into the government is seen as a way to reduce the violence.

Friday's car bomb was parked about 10 yards from the Iskan al-Shaabi mosque in the southwestern Dora neighborhood when it exploded after 1 p.m., shattering glass in the building and causing casualties inside and outside.

Police forces cordoned off the scene and prevented journalists approaching the mosque, where worshippers were attending the main weekly Muslim prayer service. At least six U.S. Humvees were in the area.

Ahmed Hassan, 36, who was praying inside the mosque at the time of the blast, said: "Terrorists are trying to drive a wedge between Sunnis and Shiites."

"Some worshippers were leaving and others were praying inside when the explosion blasted glass all over us and smoke filled the mosque," Hassan said. "Outside we were shocked to see so many wounded people and cars on fire."

At least eight people were killed and 21 wounded, according to Dr. Muhannad Jawad of Yarmouk General Hospital where the victims were taken.

Several hours after police left the scene, several masked gunmen shouting "Allahu Akbar," Arabic for "God is great," began firing randomly at people outside the mosque.

An AP photographer saw at least two onlookers shot and fall to the ground, as well as one of the gunmen holding a pistol to the head of a woman. The photographer at this point fled the scene for his safety, but heard a gunshot from behind him. It was unclear if any people were actually killed.

Elsewhere in Baghdad, Adel Khalil Dawoud, imam of the Nuaimi Sunni Muslim mosque, was dragged from his house late Thursday by at least a dozen armed men wearing police uniforms, his brother, Tahsin Khalil Azawi, said.

"Three vehicles, one with flashing police lights, came to our house and about 15 or 16 men wearing special forces uniforms got out and pushed my sister's two guards away and insulted them before breaking into the house and my sister's room saying that they wanted Adil," said Azawi.

The cleric, whose sister is a former lawmaker, Rajaa Khalil Dawoud, recently returned to Iraq from Jordan where he fled to for six months to avoid attacks by Shiites against Sunni religious leaders, his brother said.

The cleric's sister told the men that her brother was in Jordan, but they barged into his upstairs room and dragged him into one of the cars, Azawi said, blaming Shiite militiamen linked to Iraq's top Shiite political leader, Abdul Aziz al-Hakim, for the kidnapping.

Maj. Gen. Hussein Ali Kamal, the Interior Ministry's undersecretary for intelligence, said police were not involved in the abduction and investigations were under way to find the cleric.

"Those who are carrying out these operations are outlaws," Kamal said. "If we want to arrest anyone, even officials, we must obtain an arrest warrant from a court, then inform their family and carry out the arrest during daylight."