Protesters took to the streets across Iraq on Friday to mark a "Day of Rage,” with thousands flooding Baghdad's Tahrir Square as seven protesters died in clashes with police in two northern cities.

Protesters in the capital were forced to walk to the rally site as security forces imposed a vehicle ban, a day after Prime Minister Nuri al-Maliki claimed the demonstrations were being organized by al-Qaida insurgents and loyalists of deposed dictator Saddam Hussein.

A car bomb detonated by a suicide attacker in the central Iraqi city of Samarra killed 10 policemen and wounded 16 others on Monday morning, police said.

The bomber rammed his explosives-packed vehicle into a compound for an emergency response unit which had been moved to the city to help with security for Shiite mourning rituals earlier this month, a police officer said.