Anti-government protesters have clashed again with Iraqi security forces in Baghdad (Khalid Mohammed/AP)

Riot police fire tear gas while protesters set fires during clashes in Baghdad (Khalid Mohammed/AP)

Four anti-government protesters have been killed and 65 others injured amid ongoing clashes with Iraqi security forces near a strategic bridge in Baghdad.

The latest clashes came just hours after some of the most intense street violence seen in recent days, with 10 protesters killed and another 100 injured.

Security forces used tear gas and live ammunition to repel demonstrators in clashes that lasted well into the night on Thursday.

On Friday, two protesters were killed by tear gas and another was hit by live rounds fired by security forces on Rasheed Street. A fourth later died from injuries sustained earlier in the day.

The street is close to Ahrar Bridge, a flashpoint in recent days.

Grand Ayatollah Ali al-Sistani, the highest Shia religious authority in Iraq, re-emphasised calls to political parties to pass electoral reform laws and respond to the protesters' demands.

Iraq's massive anti-government protest movement erupted on October 1 and quickly escalated into calls to sweep aside Iraq's sectarian system.

Protesters continue to occupy several Baghdad squares and parts of three bridges in a stand-off with security forces.

PA Media