Iraqi Shi'ite cleric Moqtada al-Sadr has called on his followers to stop fighting government forces after a week of battles in southern Iraq and Baghdad threatened to spiral out of control.

Scores of people have been killed in the clashes and an indefinite curfew is now in place to contain further violence in Baghdad's Shi'ite neighbourhoods and other areas. The Iraqi government has welcomed Sadr's statement but stressed it will press on with its offensive in Basra which it claims targets criminals.

A crackdown on Shi'ite militants in the southern oil port of Basra has sparked an explosion of violence that risked undoing the past year's improvements in the country's security.