A high-ranking security official said four car bombs exploded near the headquarters of the Iraqi Kurds' asayesh security service in Arbil, causing an unspecified number of casualties.

Another senior security official said the first blast was a suicide car bomb, while an explosives-rigged ambulance was detonated when people rushed to check for casualties.

An AFP journalist heard three blasts in Arbil, and heavy gunfire. Smoke could be seen rising in the air, as ambulances raced to the scene.

While much of Iraq is plagued by near-daily violence that kills hundreds of people each month, the three-province Kurdistan region in the country's north is largely spared the deadly unrest.

Sunday's blasts were the first to hit Arbil since May 2007, when a truck bomb exploded near the same asayesh headquarters, killing 14 people and wounding more than 80.

The blasts came a day after results were announced for the region's parliamentary elections, which saw an opposition movement in second place ahead of Iraqi President Jalal Talabani's party.

Iraqi Kurdistan enjoys a high level of autonomy from Baghdad, and the regional parliament has passed laws on a wide range of issues.

Kurdistan also operates its own security forces and visa regime.