Over 40 people were killed when Iraqi security forces stormed a Sunni Muslim protest camp near Kirkuk.
The clashes were the bloodiest since thousands of Sunni Muslims began staging protests in December against Prime Minister Nouri al-Maliki's Shia-led government.
Iraq's defence ministry and military said troops found rocket-propelled grenades, sniper rifles, and other weapons in the camp.
But protest leaders said they were unarmed when security forces stormed in and started shooting.
Three soldiers were killed during clashes with gunmen who attacked an army convoy and burned two army vehicles on the road outside Ramadi, 100km (60 miles) west of Baghdad.
Since the last US troops left in December 2011, Iraq's government has been mired in crisis over how to share power among the Shia, Sunni and ethnic Kurdish parties.
Mr Maliki's critics accuse him of amassing power at their expense.
Many Iraqi Sunnis say they have been sidelined after the US-led 2003 invasion that ousted Sunni Saddam Hussein and allowed the Shia majority to gain power through elections.
Elsewhere, at least seven people were killed and 17 more wounded when two roadside bombs targeted worshippers as they left a Sunni mosque in Baghdad.