Political leaders in Kirkuk Wednesday urged restraint and unity after the assassination of a top Sunni Arab politician in the northern Iraqi city sparked fears of a flare-up.
Mohammed Khalil al-Juburi, who headed the Arab bloc in the Kirkuk provincial council, was killed on Tuesday night when gunmen riddled his car with bullets.
His wife Fawzia, who was also in the vehicle, died of her injuries on Wednesday morning and the pair were buried later during a funeral attended by hundreds of people.
"The assassination of Juburi and his wife was aimed at the political unity of Kirkuk's residents and their representatives," Kirkuk Governor Najm al-Din Karim told AFP by phone.
"This cowardly and terrorist act is designed to stir up conflict and create rifts between the people of Kirkuk," he said.
"But they must stand against terrorism... and maintain the province's unity," Karim said.
Iraqi Prime Minister Haider al-Abadi issued a statement in which he said he had ordered a thorough investigation into the killing.
Oil-rich Kirkuk is claimed by Iraq's autonomous Kurdish region, which currently holds a large part of the province, and by the federal government in Baghdad.
Federal forces were deployed in Kirkuk until June 2014, when they abandoned their positions when faced with an offensive by the Islamic State jihadist group that overran large parts of the country.
Kurdish forces have since battled the jihadists in Kirkuk, but IS still controls territory in the southwest of the province.
Kirkuk is one of Iraq's most ethnically and religiously diverse cities and has long been seen as a tinderbox that could erupt into a major civil conflict.
Yet it withstood several waves of violence over the years and maintained a degree of political cohesion.