Security forces have killed at least 40 protesters in Iraq as a new escalation of anti-government protests erupted in the southern city of Nasiriyah, hours after the torching of an Iranian consulate in the holy city of Najaf.

Iran's foreign ministry spokesman Abbas Mousavi condemning the attack and demanded Iraq to take decisive action.

Curfews have been ordered both in Nasiriyah and the holy Shiite city of Najaf after violent protests.