Clashes flared suddenly Friday evening as demonstrators attempted to cross Al-Sinek Bridge in the heart of the Iraqi capital, a security source told AFP.

Security forces, charged with preventing demonstrators from reaching the other side, fired tear gas, with one canister hitting a demonstrator in the chest and killing him.

A medical source said 24 people were also wounded or suffered breathing difficulties.

Angry demonstrations have rocked Baghdad and Iraq's south for the last three months, denouncing the country's political system which is seen as among the most corrupt in the world.

Since October, the unrest has seen around 460 people killed and some 25,000 wounded, the vast majority of them demonstrators.

The movement, seeking sweeping political reforms, and better jobs and services, has also faced a campaign of intimidation, abductions and assassinations.

But protests have been overshadowed by the January 3 killing of senior Iranian commander Qasem Soleimani in a US drone strike in Baghdad, sparking fears Iraq would become embroiled in a conflict between Washington and Tehran.

The strike also killed top Iraqi paramilitary commander Abu Mahdi al-Muhandis, deputy head of the Hashed al-Shaabi military network, which is dominated by pro-Iran factions.

Iran responded by firing missiles at Iraqi bases where American soldiers are deployed.

US Central Command said Thursday at least 11 American troops were injured.

Iraq firebrand Shiite cleric and political figure Moqtada Sadr has called for a "million-strong march" on January 24 to condemn the US military presence in Iraq.