GENEVA: The U.N. voiced deep concern Friday over the reported shelling and burning of homes in the Iraqi city of Tuz Khurmatu, warning of a “serious risk” that violence could escalate. The United Nations human rights office pointed to reports that residential areas of Tuz Khurmatu, in the Salahuddin governorate, had been shelled on Dec. 9 and 12, “causing casualties among civilians.”

“It is not clear who is carrying out the shelling, which is reported to be coming from the mountains overlooking the area,” agency spokeswoman Liz Throssell told reporters in Geneva.

Iraqi forces are working to determine where the shelling is coming from and who is responsible.

Tensions have been swelling in the disputed area of Tuz Khurmatu following September’s independence referendum in the neighboring Kurdistan Region.

The city’s population is a mix of Turkman, Kurd and Arab communities, and Throssell warned that “there is a serious risk that given the ethnic and religious fault lines in the area, that violence could escalate and spread.”

In recent weeks, clashes have raged between the peshmerga Kurdish security forces and Turkmen Popular Mobilization Units.

“This fighting has to date resulted in an unconfirmed number of deaths in each group,” Throssell said.

She said U.N. staff visited the city on Dec. 7 and again on the Dec.14 to investigate reports of the burning of homes and looting of businesses.

They had seen “some 150 premises that had been burned or otherwise damaged,” she said, adding that they had also spoken with people who had fled violence in the city and were currently staying in Kirkuk and Irbil.

In October, a similar number of houses were reportedly looted and burned by Turkmen PMUs and civilians, she pointed out.

As many as 11 houses reportedly belonging to Kurdish families and officials had also been destroyed by explosives in the city, Throssell said.

“Thousands of residents, mainly of Kurdish origin left for the Kurdistan Region of Iraq, apparently fearing repercussions, and to date many have not returned,” she warned.

The U.N. rights office called for an end to “all acts that threaten the fundamental rights of the Tuz Khurmatu population.”

“We also call on the Iraqi authorities to ensure that civilians there are protected and those responsible for human rights abuses brought to justice,” Throssell said.