Two protesters were killed Tuesday as anti-government demonstrations took a more violent turn in Iraq's capital and restive south, where burning tyres blocked highways and thick black smoke blanketed cities.

The deaths in clashes with security forces sent the toll from nearly two months of protests to more than 350 people dead, according to an AFP tally.

In the Shia holy city of Karbala, one person was killed as protests became chaotic "clashes" with security forces, a medical source told AFP.

There were no immediate details about the victim's identity or cause of death, but the medic said the toll was likely to rise further.

AFP's correspondent saw riot police fire live rounds both into the air and directly at crowds of teenage protesters. At least one demonstrator suffered a bullet wound to the head.

In one face-off under a bridge, teenagers threw rocks at riot police trucks, bursting into song when the vehicles screeched away. Clashes also erupted in Baghdad, where security forces fired rubber bullets and tear gas to keep demonstrators away from Al-Ahrar bridge, which leads to government buildings on the west bank of the river Tigris.

One protester died after being shot by a rubber bullet and 18 were wounded, a medical source said.

A body bearing a rubber bullet wound was also found underneath Al-Ahrar on Tuesday, but it was unclear when the person had died, the medic said. The historic districts near Al-Ahrar have morphed into arenas for daily street battles.