Iraqi security members examine the site of a bomb attack in Baquba, about 60 kilometres northeast of Baghdad. ((Helmiy al-Azawi/Reuters))

A police spokesman in Iraq's volatile Diyala province says three suicide bombings have killed at least 30 and wounded more than 40 people in the city of Baquba.

Capt. Ghalib al-Karkhi said the bombings in the mixed Shiite-Sunni city, which is roughly 60 kilometres northeast of Baghdad, targeted a local government housing office next to an Iraqi Army facility, the headquarters of the provincial council and the city's emergency hospital.

The bombings — Iraq's deadliest in weeks — come as Iraq is preparing for March 7 elections that will decide who will oversee the country as U.S. forces go home and help determine whether Iraq can overcome the deep sectarian tensions that have divided the nation since the 2003 U.S.-led invasion.

U.S. and Iraqi officials have warned repeatedly that insurgents were expected to launch attacks in an attempt to disrupt the crucial vote.

First, a suicide car bomb targeted a local government housing office next to an Iraqi Army facility. Within minutes, another suicide bomber driving a vehicle struck the headquarters of the provincial council, al-Karkhi said.

A third suicide bomber, wearing an explosives vest, rode in an ambulance with the wounded to the city's emergency hospital as rescuers and victims from the first two blasts were being rushed in for treatment, he added.

Baquba police later safely detonated a fourth car bomb found near the hospital.