BAGHDAD -- Iraqi lawmakers will hold an emergency session on Friday in an attempt to end violence in the oil city of Basra after an army crackdown on Shi'ite militia sparked fighting across the south and mass protests in Baghdad.

Authorities have imposed a three-day curfew in the capital to contain the violence, in which more than 130 people have been killed since the government launched the offensive on Tuesday against fighters loyal to Shi'ite cleric Moqtada al-Sadr.

The assault on Iraq's second biggest city has exposed deep divisions between rival factions within Iraq's majority Shi'ite community. It is also a major test for U.S.-backed Prime Minister Nuri al-Maliki's ability to prove Iraqi forces can stand on their own and allow U.S. forces to withdraw.

With violence spreading across the Shi'ite south and affecting the country's vital oil exports, lawmakers called an emergency session on Friday.

"Today (Thursday) we reviewed the situation in Basra. We agreed to hold an emergency session tomorrow to discuss the Basra situation and how to resolve it," parliament speaker Mahmoud Mashhadani told Reuters.