Reports indicate that hundreds of followers of influential Shiite cleric and political leader Muqtada al-Sadr breached Iraq's parliament on Saturday, the second time in a week, to protest the government formation efforts lead by Iran-backed groups.

According to local media, seven injured as Shia cleric Sadr's supporters clash with Iraqi security forces near Green Zone in Baghdad.

Iraqi security forces used tear gas and sound bombs to try to repel the demonstrators and caused several injuries witnessed by journalists for The Associated Press (AP). An expected parliament session did not take place and there were no lawmakers in the hall.

It is the second time in days that al-Sadr supporters have forced their way into the legislative chamber, months after elections that failed to lead to the formation of a government.

Demonstrators waved Iraqi flags and pictures of the cleric inside the legislature, an Agence France-Presse (AFP) photographer said.

Iraqi Prime Minister Mustafa al-Kadhimi directed security forces to protect demonstrators and asked them to keep their protest peaceful, according to a statement.

They entered after thousands of protesters had massed at the end of a bridge leading to the Green Zone before dozens tore down concrete barriers protecting it and ran inside, the AFP photographer reported. Some protesters on the bridge were injured and carried off by their fellow demonstrators.

Thousands of demonstrators used ropes to pull down cement barricades leading to the gate of Iraq's Green Zone, which houses official buildings and foreign embassies.

They were heeding al-Sadr's call to protest the formation of the next government lead by the Coalition Framework, an alliance of Shiite parties backed by Iran.

"We came today to remove the corrupt political class and prevent them from holding a parliament session, and to prevent the Framework from forming a government," said Raad Thabet, 41. "We responded to al-Sadr’s call. We will go to the Green (Zone). No matter the cost."

"All the people are with you Sayyed Moqtada," the protesters chanted, using his title as a descendant of the Prophet Muhammad.

Sadr's bloc emerged from elections in October as the biggest parliamentary faction, but was still far short of a majority and, 10 months on, deadlock persists over the establishment of a new government.

Al-Sadr’s party exited government formation talks in June, giving his rivals in the Coordination Framework alliance the majority they needed to move forward with the process.

Many protesters wore black to mark the days leading to Ashura, which commemorates the death of Imam Hussein, the grandson of the Prophet Muhammad and one of Shiite Islam’s most important figures. Al-Sadr's messaging to his followers has used the important day in Shiite Islam to kindle protests.

Al-Sadr has used his large grassroots following as leverage against his rivals.

On Wednesday, hundreds of his followers stormed the parliament building after the Framework alliance named Mohammed al-Sudani as their nominee for the premiership and signaled their readiness to form a government.

The protests are the latest challenge for oil-rich Iraq, which remains mired in a political and socio-economic crisis despite elevated global crude prices.

Saturday's demonstration comes three days after crowds of al-Sadr supporters breached the Green Zone despite volleys of tear gas fire from the police.

They occupied the parliament building, singing, dancing and taking selfies before leaving two hours later but only after al-Sadr told them to leave.

'We don't want those in power since 2003...'

On Saturday, security forces shut off roads in the capital leading to the Green Zone with massive blocks of concrete.

"We are here for a revolution," excitedly proclaimed protester Haydar al-Lami.

"We don't want the corrupt; we don't want those who have been in power to return... since 2003, they have only brought us harm."

By convention, the post of prime minister goes to a leader from Iraq's Shiite majority.

Al-Sadr, a former militia leader, had initially supported the idea of a majority government.

That would have sent his Shiite adversaries from the pro-Iran Coordination Framework into opposition.

The Coordination Framework draws lawmakers from former Prime Minister Nuri al-Maliki's party and the pro-Iran Fatah Alliance, the political arm of the Shiite-led former paramilitary group Hashd al-Shaabi (Popular Mobilization Forces – PMF).

But last month al-Sadr's 73 lawmakers quit in a move seen as seeking to pressure his rivals to fast-track the establishment of a government.

Sixty-four new lawmakers were sworn in later in June, making the pro-Iran bloc the largest in parliament.

That triggered the fury of al-Sadr's supporters, who according to a security source also ransacked the Baghdad office of Maliki's Daawa party on Friday night, as well as that of the Hikma movement of Ammar al-Hakim which is a part of the Coordination Framework.

"We would have liked them to wait until the government was formed to evaluate its performance, to give it a chance and to challenge it if it is not," al-Hakim said in a recent interview with BBC Arabic.

"The Sadrist movement has a problem with the idea that the Coordination Framework will form a government," he said.

"If it doesn't turn out to be Sudani and a second or third candidate is nominated, they would still object," he said.