A suicide attacker has blown up a tanker lorry at the police HQ in the Iraqi city of Tikrit, killing at least five people, officials say, according to BBC News.

A majority of the casualties and injured are thought to have been police officers.

The city, which lies 160km (100 miles) north of the capital Baghdad, was the hometown of ex-leader Saddam Hussein.

Violence has decreased in Iraq since the peak of the insurgency in 2006 and 2007, but bombings are still common.

Sunni Islamist militants linked to al-Qaeda have vowed to step up attacks on Shia and official targets this year, in an attempt to weaken the Shia-led government.

Last week, at least 19 people died and more than 100 were wounded in a spate of car bomb attacks in the northern city of Kilkurk.

The violence comes ahead of provincial elections scheduled to take place on April 20.

The country is experiencing a deep political crisis, with Prime Minister Nouri Maliki sharply at odds with a range of political forces, including the Kurds, most of the Sunni groups, and many factions within his own Shia community.