The riot police fired tear gas canisters and warning shots to disperse the protesters, but there were no clashes between the protesters and the security forces, an Interior Ministry source told Xinhua news agency.
Many videos aired by TV channels and social media showed dozens of demonstrators inside Parliament building waving Iraqi flags and chanting slogans hailing Moqtada al-Sadr.
Prime Minister Mustafa al-Kadhimi urged in a statement the protesters to withdraw from the building immediately.
Al-Sadr told the demonstrators to end the protest in a tweet late Wednesday night, saying “your message has arrived… Go back to your homes safely”.
The protest came two days after the Coordination Framework, an umbrella group of Shia parliamentary parties, nominated Mohammed Shia’ al-Sudani.
The Coordination Framework became the largest alliance in the Iraqi Parliament after al-Sadr ordered his followers in the Sadrist Movement, the biggest winner in the elections held on October 10, 2021, with 73 seats, to withdraw from Parliament.
During the past months, the continuing disputes among the Shiite parties have hampered the formation of a new Iraqi government, as Parliament has been unable to elect a new president by a two-thirds majority of the 329-seat Parliament under the constitution.
If elected, the President will appoint the prime minister nominated by the largest alliance in Parliament, the Coordination Framework, to form a new government that would rule the country for the coming four years.