The U.N. Assistance Mission in Iraq reports "dozens" of Turkmen protesters were either killed or injured during demonstrations advocating more protection for Turkmen leaders in the area known as Tuz Khurmatu.
U.N. special envoy to Iraq Martin Kobler said Iraqi leaders are called on to ensure all communities in the country are protected.
"Such attacks aim to heighten tensions in this particularly sensitive region of Tuz Khurmatu," he said in a statement.
The region lies within the jurisdiction of the semiautonomous Kurdistan Regional Government, which controls Iraq's northern provinces. Attacks in the region in January targeted the offices of the Kurdistan Democratic Party, one of the main political factions in the Kurdish north.
The U.N. Assistance Mission in Iraq said it is committed to finding a political solution to crises in the country but is frustrated with the level of violence.
The KRG and the central government in Baghdad are at odds over issues ranging from oil to territorial jurisdiction.
Human Rights Watch, in two reports, said it suspected Iraqi security forces were behind civilian attacks in northern Iraq in recent months.