On Sunday, Iraqi security forces deployed in the northern Iraqi oil city of Kirkuk to prevent further violence after clashes between ethnic groups the previous day resulted in four deaths.

The four protesters killed in Kirkuk on Saturday were Kurdish, according to police and medical sources. The clashes broke out after days of tensions between ethnic groups.

On Sunday, Kirkuk police spokesman Amir Shwani told reporters the curfew had been lifted, and vehicles were moving normally in the city.

He added that security forces had deployed additional troops to "prevent violence and protect civilians".

Since 2017, the Iraqi Army has been using a building in Kirkuk that was once the headquarters of the Kurdistan Democratic Party (KDP) as a base.

The federal supreme court of Iraq issued an urgent ruling on Sunday requiring the government to delay the handover of a building to the KDP in Kirkuk.

During discussions about the return of the powerful Kurdish party to the city, the ruling could raise tensions.

According to four Kirkuk residents who spoke to Reuters by phone, military helicopters flew over the city on Sunday.

Residents reported that police detained several people who participated in the clashes on Sunday, but police refused to comment on arrests.

The situation is tense and dangerous

Oil-rich Kirkuk, located on the fault line between the Kurdish autonomous region and Iraq's Shia-dominated central government, has been the scene of some of the country's worst post-Islamic State (IS) violence.

The KDP's return to the city has been protested by Arab residents and minority groups, who claim they suffered under Kurdish rule.

With their sit-in, "rioters" blocked the highway from Kirkuk to Erbil, according to veteran Kurdish leader Massud Barzani.

The Kurds need unity after years of setbacks

"This is creating a tense and dangerous situation for residents," he said.

On Saturday, Barzani said "violence was used against Kurdish youth and demonstrators" due to those blocking the road's chaos and illegal behavior.

His son Masrour Barzani, the prime minister of the autonomous region, called on Sudani in Baghdad "to intervene immediately to control this unacceptable situation".

Kurdish citizens persecuted in Kirkuk are also urged to show restraint and refrain from violence.

The Iraqi army ejected Kurdish forces from Kirkuk city in 2017, bringing the city back under Baghdad's control after they drove IS out in 2014.

As soon as Sudani took power last year, he improved relations with the KDP and agreed to allow the party to reopen its Kirkuk headquarters.