The Iraqi security authorities imposed a curfew in Najaf and Maysan cities.
The curfew has been in effect since 3 pm until further notice.
So far, at least 21 people have been reported killed and hundreds have been wounded since the violence and clashes between security forces and anti-government demonstrators first erupted on Tuesday.
In a desperate attempt to quell the protests, which were in part spurred by woes over deteriorating economy and lack of jobs and services, authorities have cut Internet access across much of Iraq.
Before dawn, explosions were heard inside Baghdad’s heavily fortified Green Zone, home to government offices and foreign embassies. The U.S.-led coalition said an investigation is underway, adding that no coalition forces or assets were hit.