A policeman was killed on Sunday in Iraq, the army said, as security forces fired to disperse a third consecutive day of protests in the city of Nasiriyah, according to medics.

The policeman was "killed by a bullet to the head", a medic in the city 300 kilometres south of the capital Baghdad said.

The army confirmed the death. "Thirty-three other policemen were wounded in the events of the day," the military added, without elaborating.

Medical sources said several protesters were wounded.

Witnesses said security forces opened fire to disperse demonstrators — including some throwing stones — from a city square that served as an epicentre of a widespread protest movement that began in October 2019.

A sprawl of tents in Habbubi Square had remained in place until November 2020, when eight people were killed in clashes between anti-government protesters and followers of the Shiite leader Moqtada Sadr.

Anti-government protesters reoccupied the square on Friday, demanding the release of peers who have been arrested in recent weeks.

Security forces repeatedly fired in the air and launched smoke grenades towards the protesters, whose movement for the first time penetrated other parts of the city.

A spokesman for the protesters told AFP that 13 demonstrators who had been arrested were released, adding that authorities had promised other detainees would be released the next day.

Iraq's protests fizzled out last year due to the COVID-19 pandemic and a crackdown that left nearly 600 dead and 30,000 wounded.

But kidnappings, targeted killings and arrests of protest leaders have continued.

Alongside demanding an end to political corruption, protesters want jobs and improved public services.

But the state's ability to finance these demands is hamstrung by an economic crisis, including a yawning fiscal deficit.