By Mohammed Tawfeeq, CNN
BAGHDAD (CNN) — At least 20 people were killed and more than 35 others wounded when a suicide car bomber followed by gunmen in police uniforms attacked the police headquarters in the northern Iraqi city of Kirkuk on Sunday, city police said.
The interior ministry in Baghdad placed the casualty count higher: 30 dead and 70 wounded.
In the immediate chaotic aftermath of the attack, exact figures were difficult to come by.
The oil-rich Kirkuk, about 240 kilometers (150 miles) north of Baghdad, has been the scene of tensions recently. It is also one of the disputed areas in the country between the central government and Kurdistan regional government.
Last month, a series of bombings there killed dozens and left more than 100 wounded in violence that seemed targeted at Kurdish government officials.
The Iraqi central government and the Kurdistan regional government have been at odds for years over who has final authority over Iraq’s vast oil wealth.
At the end of last year, relations between Prime Minister Nuri al-Malik’s government and the Iraqi Kurds seemed to deteriorate further.
In November, Iraqi Kurdistan deployed troops and tanks to cement the Kurds’ claim over the strategic city. This launched a tense standoff with units of the Iraqi army, which had been deployed to areas near Kirkuk.