The bomb blasts occurred about 10am on Wednesday in five neighbourhoods of Baghdad, as the country marked the 11th anniversary of the fall of the Iraqi capital during the US-led invasion that ousted Saddam Hussein.

They came a day after Iraq's security forces said they killed 25 militants near Baghdad, amid worries that insurgents are encroaching on the city ahead of April 30 elections.

On Wednesday, three people were killed and eight wounded in the explosion of a car parked in the northern Baghdad neighbourhood of Kadhimiya, a health ministry official said.

"In Sadr City, in eastern Baghdad, a car bomb that exploded in a vegetable market killed one person and six wounded," the official said.

Two more people were killed and eight wounded when another bomb went off in a car park elsewhere in the east of the capital.

A fourth car bomb left one person dead and eight wounded in Shaab, in north-eastern Baghdad, the health ministry official added.

A police colonel said two car bombs that blew up simultaneously wounded seven people at Al-Andalus Square in the central Baghdad neighbourhood of Karrada.

Violence across Iraq has killed more than 2400 people this year, sparking fears the country is slipping back into the all-out sectarian fighting that plagued it in 2006 and 2007.

The bloodshed has been driven principally by anger in the Sunni community over alleged mistreatment at the hands of the Shiite-led government and security forces, as well as spillover from the civil war in neighbouring Syria.

AFP