KIRKUK, Iraq (Reuters) - Two suicide bombers killed at least five people and wounded more than 20 in an attack on a Shi’ite mosque in the northern Iraqi city of Kirkuk on Sunday, police and medical sources said.

It was the first such attack since the central Iraqi government in Baghdad seized Kirkuk last month from Kurdish forces that had controlled the oil city of a million people for three years.

Acting Kirkuk governor Rakan Saeed appealed to Iraqi Prime Minister Haider al-Abadi after a meeting of the provincial security panel to send more troops to secure the city.

“Deployed forces from police and Counter Terrorism Service are not enough to cover all areas of Kirkuk. We need to double the troops,” he said in a statement after chairing the meeting.

The interior ministry confirmed the attacks on a mosque on Atlas Street in the center of Kirkuk and gave an initial casualty toll of one dead and 16 wounded.

The central government in Baghdad recaptured the city in October along with other territory in northern Iraq claimed by both Baghdad and the Kurds following an offensive launched in retaliation for the Kurdish independence referendum.

Iraqi security forces forced the Kurdish Peshmerga to withdraw from Kirkuk and their retreat also allowed Baghdad to take control of all the oilfields operated by the state-owned North Oil Company in Kirkuk’s northern province.

No group has claimed responsibility for Sunday’s attacks but the suicide bombings are a trademark of Islamic State militants.

Police sources said the attacks happened in quick succession and the death toll might rise because some of the wounded were in a critical condition.

“It’s a crowded street and a place for street vendors. The terrorists wanted to kill a large number of people,” said a police major in Kirkuk.

In a separate incident, unknown gunmen opened fire with light weapons on a police patrol in eastern Kirkuk, without causing any casualties, police sources said.

Iraqi security officials have said Islamic State is likely to wage an insurgency in Iraq after its self-proclaimed caliphate all but collapsed and the militants were dislodged from large areas of the west and north of the country.

Iraqi security forces have recaptured nearly all the territories once controlled by Islamic State. Fighting is ongoing in the border areas with Syria where militants are entrenched in the small town of Rawa and nearby areas.