Around 50 others more wounded, several in critical condition, when security forces tried to retake two bridges in the city that had been blocked by the protesters, the sources said, after reporting an earlier toll of two dead.

Southern Iraq and the capital Baghdad have been gripped by nearly two months of rallies demanding a deep-rooted overhaul of the ruling system, seen by protesters as corrupt and inefficient.

The violence in Nasiriyah came a day after protesters torched the Iranian consulate in the holy Shiite city of Najaf, in anger at the neighbouring country they blame for propping up the Baghdad government.

The street violence in Iraq has left more than 350 people dead and some 15,000 wounded over the past two months.