At least 26 people died in a deadly clash between Iraqi security forces and Sunni anti-government protesters in the northern city of Kirkuk on Tuesday.
The deadly firefight will likely only increase already high sectarian tensions between Iraq's Sunni Muslim minority and the Shiite-led government of Prime Minister Nouri al-Maliki.
The United Nations' spokeswoman in Iraq, Eliana Nabaa, told Al Jazeera that there had been multiple casualties. She urged all involved to stop the deadly fighting.
Iraq's Defense Ministry said in a statement that government forces had been fired on first, forcing troops to kill "militants who were using the demonstration as a safe haven."
"When the armed forces started ... to enforce the law using units of riot control forces they were confronted with heavy fire," the defense ministry said.
But Ahmed Hawija, a student who had participated in the demonstrations, told Reuters that protesters were unarmed when the security forces arrived and started shooting.
"When special forces raided the square, we were not prepared and we had no weapons, they crushed some of us in their vehicles," Hawija said.
Recent protests began in December after government forces arrested the bodyguards of Sunni Finance Minister Rafia al-Issawi in a counterterrorism operation, which some have dismissed as a purely political move.
Also on Tuesday, two bombs exploded near a Sunni mosque after morning prayers at around 5 a.m, killing five people and wounding 21. No one has claimed responsibility for the attack.