The death toll from a bloody night of attacks by unknown gunmen targeting anti-government protesters in Baghdad has risen to 25, Iraqi officials said.

More than 130 other people were injured.

Iraq Protests
A protester holds a blood-stained flag at the scene of the gun attack in Baghdad (Ali Abdul Hassan/AP)

The attack was among the deadliest since October 1, when thousands of Iraqis took to the streets calling for sweeping political reforms and the end of Iran’s influence in Iraqi affairs.

Security forces regularly use live rounds and tear gas to disperse the demonstrations, leading to heavy casualties.

The gunfire continued until the early hours of Saturday morning.

The assailants first unleashed the deadly assault on Baghdad’s Khilani Square and Sinak Bridge, driving through the areas that are the epicentre of the popular uprising.

Iraq Protests
People hold national flags and chanting religious slogans march in Tahrir Square in Baghdad (Hadi Mizban/AP)

Anti-government activists have sought to blame supporters of Iran-backed Iraqi militias, which have staged similar attacks against protester sit-ins in the capital and the country’s southern cities.

Iraqi security forces were deployed to streets leading to the square by the early morning.