Also on Friday, a dozen men wearing Iraqi police uniforms snatched a Sunni Arab cleric from his Baghdad home, while abducted Jill Caroll, the US reporter, appealed to supporters in a new tape to do whatever necessary to secure her freedom.
The car which targeted the Iskan al-Shaabi mosque was parked about 10 metres from the place of worship in the southern Dora neighbourhood when it exploded after 1pm, shattering glass in the building and causing casualties inside and outside, said police Lt Thaer Mahmoud.
At least eight people were killed and 21 wounded,
according to Dr Muhannad Jawad of Yarmouk General Hospital.
Earlier, police spokesman Lt Mohammed Khayoun said most of the victims were attending the main weekly Muslim prayer service.
The US military announced on Friday that two American Marines were killed a day earlier after their patrol was attacked by a roadside bomb near the one-time anti-US stronghold of Falluja, 65km west of Baghdad.
Their deaths took the number of US military personnel killed to at least 2269 since the Iraq war began in March 2003, according to an Associated Press count.
Adnan al-Dulaimi: We hope the
hostages will be freed unharmed
Adel Khalil Dawoud, imam of the Nuaimi Sunni Muslim mosque in Baghdad's northern Shaab district, was taken from his home shortly after midnight, relatives and eyewitnesses told investigating police officers, said Lt Mohammed Khayoun.
Eyewitnesses told police that 12 men wearing Interior Ministry special forces uniforms knocked on the imam's door in central Baghdad's Karradah neighbourhood early on Friday, asked for proof of identity and drove him away in one of three four-wheel drive vehicles, said Khayoun, the police spokesman.
Interior Ministry officials had no immediate comment on whether those who detained Dawoud were actually police officers or people in disguise.
Sunni leaders cite a spate of kidnappings and killings of Sunni Arabs as examples of the discrimination they face in post-Saddam Hussein Iraq, where Interior Ministry forces are now controlled by Shia Muslims who had long been suppressed under the ex-president's regime.
Sectarian violence threatens fragile US-backed political negotiations to form a national unity government that would see dominant Shia and Kurds welcome Sunni Arabs into powerful positions.
Sunni Arabs form the backbone of the raging insurgency, and bringing them into the government is seen as a way to reduce the violence.
Adnan al-Dulaimi, leader of the prominent Sunni Arab Iraqi Accordance Front, which won 44 seats in 15 December elections for the 275-member parliament, condemned Dawoud's kidnapping.
Carroll appealed in a third video
for abductors' demands to be met
"These kidnappings have increased lately and include the abduction of men and women, Iraqis and non-Iraqis," he said.
"We condemn these operations and we hope that the kidnappers would release these hostages unharmed."
Al-Dulaimi, who 28-year-old Carroll was scheduled to interview when she was abducted on 7 January in Baghdad, demanded Iraqi authorities to end such kidnappings and "restore security."
The Christian Science Monitor freelance reporter was seen late on Thursday in the third video aired since her 7 January abduction by a group called the "Revenge Brigades."
She appealed in a calm, composed voice for her supporters to do whatever it takes to win her release "as quickly as possible."
In the 22-second tape, Carroll, who wore a headscarf, said the date was 2 February and that she had sent one letter and was sending another to "prove I am with the mujahideen."
The tape was broadcast by private Kuwaiti station Al Rai TV.
Two other videos of Carroll were aired by Aljazeera.
In the first video aired on 17 January, Aljazeera said her abductors gave the United States 72 hours to free female prisoners in Iraq or she would be killed.
The next was broadcast on 30 January showing Carroll weeping, and the station said she appealed for the release of female Iraqi prisoners.
Five Iraqi women have already been freed, but Iraqi and US officials said their releases were routine and not part of a swap for Carroll.
US forces are expected to release about 450 male Iraqi detainees next week, but none of the five women remaining in Iraqi custody are among those to be freed, said deputy Iraqi Justice Minister Busho Ibrahim Ali.
"I sent you a letter written by my hand, but you wanted more evidence," she said.
"I am here. I am fine. Please just do whatever they want, give them whatever they want as quickly as possible. There is very short time. Please do it fast. That's all"
"I am here. I am fine. Please just do whatever they want, give them whatever they want as quickly as possible. There is very short time. Please do it fast. That's all."
Al-Rai's newscaster said the station would hand Carroll's handwritten letter that accompanied the tape to
authorities, but would not disclose the letter's content.
"The (US) embassy customarily works closely with our contacts with the Kuwaiti government and will seek their cooperation on this matter as well," said Tania Anderson, spokeswoman for the US mission in neighbouring Kuwait.
The Christian Science Monitor said it was seeking more information about the letter.
"It is always difficult to see someone speaking under coercion and under these circumstances," the Monitor's editor, Richard Bergenheim, said in a statement.
"We remain in constant contact with Jill's family and are still doing everything possible to obtain Jill's release."
After Thursday's broadcast, Carroll's family issued a brief statement through the Monitor, saying only that "the family is hopeful and grateful to all those working on Jill's behalf."
US officials have refused to discuss Carroll's kidnapping for fear of endangering her life. She was one of five foreigners kidnapped here last month, including two German engineers and two Kenyans.
However, some Iraqi and foreign security officials not directly involved in the case believe that in virtually all kidnappings, ransom money is the main goal and kidnappers present political or other demands to justify the act to their supporters.