The Special Representative of the United Nations Secretary-General for Iraq, Jeanine Hennis-Plasschaert, expressed her concern over the violence practices during the recent protests in Baghdad and other provinces.
She called for calm and deeply regreted the casualties among both the protesters and security forces.
The Special Representative reaffirmed the right of Iraqi people to protest saying, "Everyone has the right to speak freely, in accordance with the law."
Ms. Plasschaert urged the authorities to exercise restraint in dealing with protests to ensure the safety of peaceful protesters while upholding law and order and protecting the people, public and private property.
Hundreds took to the streets of the capital and other Iraqi provinces on Tuesday in the first major challenge to the government.
Security forces fired tear gas and live rounds to disperse the crowds, leaving one dead and 200 wounded in Baghdad and another protester dead in the south, health officials said.
The violence drew condemnation from President Barham Saleh, who urged "restraint and the respect for the law".
"Peaceful protest is a constitutional right granted to citizens," he said late Tuesday.
The demonstrators in Tahrir Square in the heart of Baghdad voiced a range of grievances -- state corruption, failing public services, unemployment and even the sidelining of a popular Iraqi general last week.
Unusually for Iraq, no political faction had explicitly called for the protest, which appeared to be largely spontaneous.
By early evening, it had degenerated into violence, with riot police using tear gas and water cannons and then opening fire with live and rubber bullets to disperse the crowds.
Heavy gunfire could be heard into the night around Tahrir Square. It was not clear if bullets were fired directly at protesters or into the air.
On Wednesday morning, Tahrir Square remained sealed off by a heavy police presence.
Parliament has ordered an investigation into the violence. Its human rights committee has already criticized security forces for their "suppression" of the demonstrations.