A spokesman for Iraq's autonomous Kurdish region says four people were killed when a suicide bomber detonated an explosives-laden vehicle near the provincial government headquarters in the capital Irbil.
Spokesman Hamza Hamed said the blast hit the main checkpoint on the way to the headquarters, close to the historic citadel in the city center.
Hamza said at least three of those killed were security guards.
Iraq's Kurdish region is generally free of the violence that affects other parts of the country.
But Kurdish peshmerga forces are currently battling the Islamic State militant group, making Kurdish areas a more prominent target for militants.
Irbil is close to the front lines. IS militants advanced within 30 kilometers of the Irbil last summer, but were eventually repelled by the peshmerga with the help of U.S. air strikes.
Based on reporting by AP, AFP, and BBC