Security forces early Thursday ended an hours-long siege at a mall in the northern city of Kirkuk but not before militants killed nine people, security officials and medics said.

The attack Wednesday on the mall in the oil rich ethnic tinderbox city, which involved a car bomb and would-be suicide bombers, came amid a surge in unrest that has claimed more than 6,200 lives this year.

Attacks by militants were also launched Wednesday in Baghdad, Mosul, Tikrit and Fallujah, but the assault on the Jawaher Mall in Kirkuk was the deadliest.

A car bomb went off early afternoon in front of a branch of police intelligence, and was swiftly followed by a firefight between security forces and militants who were ostensibly trying to take over the security station.

As the clashes continued, gunmen, some of them wearing suicide vests, stormed the adjacent mall, took shoppers hostage and moved up the five-storey complex to the roof, from where they opened fire on security personnel who attempted to enter.

At around midnight, security forces finally stormed the mall, which contains more than 100 shops including stores specialising in women's fashion and cosmetics, as well as men's clothing and other goods.

They managed to release the 11 hostages unharmed, but security and medical officials said nine people were killed in the attack, including eight members of the security forces, while at least five militants were also shot dead.

The mall, which is popular with middle-class residents of the northern oil hub, lies in a neighbourhood populated mostly by ethnic Turkmen.

Kirkuk has a mixed population of Arabs, Kurds and Turkmen.

It lies at the centre of a swathe of territory stretching from Iraq's eastern border with Iran to its western frontier with Syria that Kurdish leaders want to incorporate into their autonomous region in the north over strenuous objections from the central government in Baghdad.

Militants often exploit poor communication between the Iraqi army and Kurdish security forces to carry out attacks in the city.

Attacks in Baghdad, Mosul, Fallujah and near Tikrit, killed three more people on Wednesday, officials said.

Officials have blamed the upsurge in violence to a resurgent Al-Qaeda emboldened by the civil war in neighbouring Syria, but the government has itself faced criticism for not doing enough to address the concerns of Iraq's disaffected Sunni Arab minority ahead of April elections.

Despite a near-ubiquitous security force presence in major cities nationwide, attacks have hit targets ranging from cafes and football grounds to military checkpoints and government vehicles, with more than 6,200 people killed so far this year, according to an AFP tally.

The violence has forced the authorities to appeal for international help in combatting militancy.