An Iraqi protester was killed in Baghdad on Tuesday, medics said, as angry young people reignited a three-month-old protest movement by shutting roads to pressure authorities to implement long-awaited reforms.

The demonstrator died after being hit by a tear gas canister on one of the main highways in east Baghdad.

Protesters had been trying to shut down the road with burning tyres but clashed with security forces, who fired live rounds and tear gas to break up the crowd.

Eight protesters were also treated for tear gas inhalation, medics said.

On Monday, three demonstrators were killed in the capital.

Iraqi protesters block the airport highway in the Shiite shrine city of Najaf, a major draw for foreign pilgrims
Iraqi protesters block the airport highway in the Shiite shrine city of Najaf, a major draw for foreign pilgrims AFP / Haidar HAMDANI

Security forces have relied heavily on tear gas to confine protesters to Baghdad's Tahrir Ssuare, but human rights groups have accused them of improperly firing the canisters directly into crowds at point-blank range, piercing protesters' skulls and chests.

Anti-government rallies have rocked Iraq since October but had thinned out in recent weeks amid spiralling tensions between Baghdad's key allies Tehran and Washington.

To regain momentum, protesters had given the government until Monday to address their demands: early elections under a new voting law, an independent prime minister and for corrupt officials to be held accountable.

Since the deadline expired, clusters of young protesters have taken to the streets of Baghdad and across the Shiite-majority south every morning.

On Tuesday, they set up impromptu roadblocks in the southern cities of Amarah, Basra, Diwaniyah and Kut.

Security forces have relied heavily on tear gas to confine protesters to Baghdad's Tahrir Square, but human rights groups have accused them of improperly firing the canisters directly into crowds at point-blank range
Security forces have relied heavily on tear gas to confine protesters to Baghdad's Tahrir Square, but human rights groups have accused them of improperly firing the canisters directly into crowds at point-blank range AFP / AHMAD AL-RUBAYE

In Nasiriyah, central districts were packed with protesters, most of them students carrying Iraqi flags, an AFP correspondent reported.

"With our souls, with our blood, we sacrifice ourselves for you Iraq!," they chanted, as fellow protesters blocked the main highways north and south.

That left hundreds of goods lorries stuck on the road, including some oil tankers.

Tahseen Mohannad, a demonstrator in Nasiriyah, said young people would not be deterred.

"We came out today to support the protests that won't stop despite the procrastination of the state and the political parties when it comes to our just demands," he said.

"We spilled blood over this and we will do so again, the blood of young people, in order to get rid of the unjust ruling class."

Iraq's political parties are locked in negotiations over the choice of a new premier to replace Adel Abdel Mahdi, who stepped down in December but has stayed on in a caretaker role.

The stalemate comes amid a continuing wave of rocket attacks on areas where US diplomats and troops are based.

Late Monday, three rockets hit near the US embassy in Iraq's high-security Green Zone, security sources told AFP.

As usual, there was no claim of responsibility but this time Abdel Mahdi has ordered an investigation into the incident.

Iraq