Shiite groups brokered a reported ceasefire today with militants fighting US and Iraqi forces in Baghdad’s Sadr City as the country’s army launched an offensive against al-Qaida’s main bastion in Iraq – the northern city of Mosul.

Radical Shiite cleric Muqtada al-Sadr has threatened to lift a six-month ceasefire, credited with helping to reduce violence in Iraq, by the end of the week, a spokesman and another official said today.