"According to the latest toll, there are nine dead and 26 wounded," said an Interior Ministry source.
The explosion occurred during Friday prayers.
A police official earlier said five were killed and 25 hurt in the attack at al-Subaih mosque, in the southeast of the capital.
"Some witnesses said they saw a bomber in the car, a white BMW, but we are checking these reports," he added.
Two houses were damaged in the attack, the source at the ministry said.
The explosion occurred during
One section of the mosque collapsed. Frantic worshippers in blood-spattered clothes searched through the rubble for loved ones, as wailing women beat their chests in grief.
Body parts littered the ground. One man clutched a child's foot, shaking and weeping.
"I was inside the mosque when the explosion happened, and I saw many dead and injured," said worshipper and grocery store owner Abd al-Allah Faraj.
"This is a cowardly and savage act that aims to create conflict among Iraqis," he said.
An adviser to Iraq's interior minister escaped an assassination attempt on Friday in al-Dura district south of Baghdad, Aljazeera learned.
Armed men opened fire at a car that was carrying the adviser, Sami al-Anbaki, and former director of Baghdad traffic police Major General Tariq Abd Lafta, who was wounded in the attack.
US soldier killed
One US soldier was killed and another wounded when a bomb exploded near their patrol vehicle in northern Iraq, the US military said in a statement.
The attack took place early on Friday north of Tal Afar, about 80km west of Mosul, at 2.30am local time, the statement said.
Clashes between fighters and US and Iraqi forces are common in the region.
Clashes between fighters and US
forces are common in Tal Afar
"The names of the soldiers are being withheld pending next-of-kin notification," it added.
As of Thursday, 1563 members of the US military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.
The US Defence Department said 1189 died as a result of hostile action.
Aljazeera reported seven Iraqi police officers were injured, including a brigadier, in a roadside bomb attack in the centre of Basra.
The blast destroyed the vehicle in which they were travelling.
Captors who seized three Romanian journalists in Iraq have given the Romanian government four days to withdraw its troops from Iraq, Aljazeera reported on Friday.
It broadcast a video it had received, showing the two men and a woman who were abducted on 28 March in Baghdad.