The death toll of attacks on Shiite pilgrims in Baghdad carried out in quick succession by three female suicide bombers on Monday rose to at least 25, while another suicide bombing targeting crowds at a protest in Kirkuk caused seven fatalities.

An Iraqi military spokesman, Qasim Atta, confirmed that three women wearing explosive belts carried out the attacks at three sites in the central Karada district. A further 40 people were injured in the blasts.

The bombers struck convoys of pilgrims passing through Karada on their way to a Shiite shrine in Kadimiya in northwestern Baghdad to mark the death of a revered eighth-century imam, Musa al-Kazim.

Thousands of Iraqi forces along with US reinforcements have been deployed in Kazimyah amid heightened security as the district was the site of previous attacks on pilgrims.

A team of female guards has been deployed for the first time in order to search women for explosive vests.

On Sunday, seven pilgrims on their way to the shrine were shot dead by unknown assailants. The attacks occurred in the town of Madain, south of Baghdad.

In the northern city of Kirkuk, a suicide bomber killed at least seven people and wounded 30 as thousands of people were staging a protest in the city against the ratification of an election law, a security official was cited by the Voices of Iraq news agency.

A senior police official, General Sarhad Qadir, said the attacker wearing an explosive belt targeted protestors gathering at the centre of Kirkuk.