Several rockets fired from inside Baghdad on Saturday struck the capital's fortified Green Zone area, which houses most of Iraq's key institutions and main embassies, officials said.

"Several Katyusha rockets fired from the Baladiyat and Palestine Street areas landed in the Green Zone," the Joint Operations Command said in a statement.

Those two neighbourhoods are in northern Baghdad, on the other side of the Tigris River, which runs through the city.

The incident came hours after seven people were killed when protesters, most of them supporters of Shia cleric Muqtada al-Sadr, tried to force their way through a security cordon to reach the Green Zone.

BREAKING: Reports of several rockets or mortars fired at the Green Zone in #Baghdad. - @BaxtiyarGoran — Conflict News (@Conflicts) February 11, 2017

An MP who lives in the Green Zone said at least six rockets hit the area, and a diplomat also contacted by AFP said he heard four.

Police and interior ministry officials confirmed that several rockets were fired at the vast protected area but could not specify what the presumed target was, nor whether there were any victims.

At least seven people were killed earlier as clashes broke out between police and anti-government demonstrators.

Thousands of protesters attempted to march on the fortified area in protest over corruption and the perceived bias of the election commission, local media reported.

Six protesters and one member of the Baghdad security forces were killed during the unrest, the head of the force said.

A police spokesperson said some of the protesters had been found to be armed with knives.

At least 11 other people, including protesters and members of the security forces, were also injured in the clashes - police used tear gas and fired rubber-coated bullets to try to disperse the crowds.

Peaceful protesters in #baghdad injured and reports talking about 1 killed after security forces of green zone opened fire pic.twitter.com/J5OsoFPc0S — Hamzoz حمزوز (@Hamzoz) February 11, 2017

The protests were called by the influential cleric Sadr, who urged supporters to occupy the capital's international Green Zone, which is home to the country's key institutions as well as major Western embassies.

The protest started peacefully and several speakers addressed the large crowd on Tahrir square before some of the demonstrators broke away and attempted to break through a security cordon guarding the main road to the Green Zone.

Security forces called in large numbers of reinforcements but were unable to prevent a crowd of protesters crossing Republic Bridge, which straddles the Tigris River, on the way to the Green Zone.

However, the protest was dispersed before the crowd reached the Green Zone.

Sadr eventually called for a "tactical withdrawal" to protect civilians, accusing Prime Minister Haider al-Abadi personally of being responsible for what he called "excessive force" on the part of security forces.

In response to the protests, the head of the electoral commission refused to step down, calling the protests a "Shia-Shia dispute".

Sadr has been demanding deep political reform since last year, arguing that the current rules were tailored for Iraq's leading parties, which he accuses of corruption and nepotism.

The protesters, most of them waving Iraqi flags, argued that the Independent High Electoral Commission is anything but independent.

The present seat allocation system for parliament was adopted before 2014 parliamentary polls, after small parties made significant gains in provincial elections a year earlier.

Sadr supporters held a string of massive rallies last year, which on two occasions saw protesters break into the Green Zone.

Tear gas injured some protesters in baghdad near GreenZone #iraq pic.twitter.com/2AKI3ASvfb — Hamzoz حمزوز (@Hamzoz) February 11, 2017

Those demonstrations were halted four months ago when tens of thousands of members of the security forces launched Iraq's largest military operation in years aimed at retaking the city of Mosul from the Islamic State group.

The announcement last month that elections will take place in September, however, has brought the domestic political agenda back to the fore, with Sadr's supporters looking set to resume their campaign of street protests.