Iraqi Prime Minister Haidar al-Abadi has been urged by other political leaders to resign over the outbreak of deadly unrest in the southern port city of Basra.
"We demand the government apologize to the people and resign immediately," said Hassan al-Aquli, a spokesman for the political list of Shi'ite cleric Muqtada al-Sadr, which won the most seats in the May elections.
The Conquest Alliance list, the second-leading bloc in parliament, also called on Abadi to resign, shortly after an emergency meeting of the parliament to discuss the unrest in Basra, where 12 protesters were killed, the Iranian Consulate and other government buildings were torched, and the airport was hit by rockets.
A curfew imposed the previous day was lifted on September 8 as the streets were quiet under a heavy security force presence.
Organizers of the demonstrations in Basra had vowed to pause for one day.
The Basra protests began when some 30,000 people fell ill from polluted drinking water.
Abadi described the several days of unrest in Basra as "political sabotage" and said that the quality of "public services" was being exploited for political means.
Abadi's government announced that extra funds would be provided to Basra.
The Health Ministry said that 50 people -- 48 civilians and two police officers -- had been injured during the protests.
News agencies quoted Basra residents and protesters as saying they have become angered by corruption, mismanagement, and a collapse of infrastructure that has led to a loss of electricity and safe drinking water in the blazing summer heat.
Protesters had set the Iranian Consulate on fire to protest what they see as Iran's excessive influence in Iraqi domestic affairs.
The Iranian government condemned the attack, in which there were no reported injuries. "We expect the immediate arrest and punishment of the attackers," Foreign Ministry spokesman Bahram Qassemi said.
Iran and Iraq -- enemies in a brutal eight-year war that ended in 1988 -- have developed closer ties since Iraqi dictator Saddam Hussein was toppled in 2003 by a U.S.-led invasion.
Shi'a-led Iran has become heavily involved in Iraq's political affairs and sponsors powerful Shi'ite militia groups that played a role in defeating Islamic State (IS) extremists last year.
Iraq's population is 60-65 percent Shi'ite, 15-20 percent Sunni Arab, and 17 percent Sunni Kurd, creating a tense balance of power in the country.
Smaller protests have been reported in other cities, including the capital, Baghdad, and Karbala.