In the capital some protesters retook to the main protest camps in Tahrir and the Tayaran Squares, while others burned tires to block highways and bridges, turning back cars and prompting traffic jams.
"We want to send a message to the government: Stop procrastinating. The people know what you're doing," protester in Baghdad told AFP.
In the holy city of Najaf, people lit tires and began a sit-in on the main road leading to the capital.
Rallies also expanded to the southern cities of Diwaniyah, Kut, Amara, and Nasiriyah, where most public offices, schools, and universities have been shut down for months.
The mostly youth-led movement is demanding early elections based on reformed voting law, a new prime minister to replace current caretaker Adel Abdel Mahdi and alleged corrupt officials to be judged.
"We want rapid elections and an independent candidate who doesn't belong to the old parties," protester Jassim Abbas told Al Jazeera.
Police used tear gas to try to disperse the protesters who responded by throwing rocks. Clashes led to at least 10 people including police officers injured, a medical source told AFP.
After PM’s Abdel Mahdi resignation last November, political parties have been unable to agree on a successor, while demonstrators have discarded all the names circulating as possible replacements.
The uprising is the largest and bloodiest that have taken place in Iraq in decades. Almost 460 people died and more than 25,000 were wounded since October.