An Iraqi military officer and six soldiers were wounded on Wednesday as rockets hit Baghdad’s Green Zone, after parliament met for its first session in two months.
At least three rockets hit the heavily fortified seat of government as MPs gathered under tight security.
The parliamentary sessions were suspended in late July after an intervention from Moqtada Al Sadr, who was disgruntled over his failure to form a government.
The influential Shiite cleric ordered his supporters to break into the legislative body to derail the formation of a government by his rivals.
Politicians voted against the resignation of Parliament Speaker Mohammed Al Halbousi and elected a Deputy Speaker. But outside of the Green Zone, large crowds of Sadrist protesters gathered near concrete walls surrounding the government centre, moving on to Jumhuriyah bridge — which was a scene of bloodshed during anti-government protests in 2019, when hundreds of protesters were killed.
By early evening, Mr Al Sadr's supporters had moved an armoured bulldozer to the area but were forced to retreat when security forces fired teargas.
Similar scenes played out in Basra, where protesters briefly took over a large government complex, before being forced out by riot police. There were no reports of casualties in the southern port city.
Analysts and politicians said the move may serve as a vote of confidence for Mr Al Halbousi, a former ally to Mr Al Sadr. He is seeking to strengthen his position in the negotiations to form a new government with other factions.
Mr Al Halbousi’s resignation was rejected by 222 out of 235 MPs who attended, renewing his mandate.
Shortly after the session, rockets landed inside the Green Zone, a security official said.
The UN mission to Iraq (Unami) called for calm and restraint.
"We call on all to refrain from intimidation, threats and violence. There are solutions. But for solutions to see daylight, constructive and timely dialogue is essential," Unami said in a statement.
Iraqi security forces sealed off the main bridges and roads leading to the Green Zone on Tuesday night. This happened after Mr Al Sadr's supporters called for protests in Baghdad and some of the country's provinces on social media.
“We warn the legislative authority not to hold the session and not to form a government that will be a tool in the hands of the corrupt political parties and rogue militias,” an unidentified man flanked by a group of others in Baghdad's Kadhimiya district said in a video, one of many published by Sadrists from across Iraq.
New blast walls have been erected around the Green Zone, which is home to many state institutions. In some sections, two lines of blast walls have been erected.
Dozens of protesters converged on Baghdad's Tahrir Square, holding Iraqi flags and chanting pro-Iraq slogans with no mention of Mr Al Sadr.
“Whatever it takes, we will stop them, the people are still strong,” they chanted.
The security measures jammed traffic in the capital, forcing many Iraqis to walk.
Wednesday's session came after nearly a year of political deadlock that followed a bitterly disputed election result and mounting violence.
The October national elections were the fifth parliamentary vote for a full-term government since the 2003 US-led invasion that toppled Saddam Hussein.
Mr Al Halbousi, a young Sunni leader, made significant gains in the elections. These allowed him and the Kurdistan Democratic Party to team up with Mr Al Sadr to form a majority government.
But the process has repeatedly stalled after a coalition of mainly Iran-linked parties, the Co-ordination Framework, mounted legal challenges and boycotts of parliament sessions.
Mr Al Sadr ordered his MPs to resign and withdraw from the government formation in protest, leaving Mr Al Halbousi and the Kurdish Democratic Party to find new allies.