A suicide bomber has killed 12 people and injured  15 others in the town of Musaib, 80km south of the Iraqi capital Baghdad, police have said.

The attack took place in a Shia mosque during prayer time on Friday, a day after parliamentarians passed a controversial security pact with the US.

The mosque was filled with around 300 worshippers when the bomber attacked,  Kadhim al Shammari, a police officer, said.

In July 2005 more than 70 people were killed in the same mosque when a suicide bomber detonated explosives loaded on a lorry.

The mosque is mainly used by worshippers who follow Muqtada al-Sadr, a Shia leader.

Politicians loyal to al-Sadr strongly opposed the security pact which the parliament approved on Thursday, which allows US troops to remain in Iraq for another three years.