A suicide bomber detonated an explosives-rigged vehicle in the usually secure Iraqi Kurdish regional capital Arbil Wednesday, killing four people in an attack blamed on the Islamic State (IS) group.
The bomber hit the main checkpoint on the way to the provincial government headquarters in the northern city just before noon (0900 GMT), provincial council spokesman Hamza Hamed said.
In addition to the four dead, two of them police, 29 were wounded, said Saman Barzanchi, the director general of the Arbil health department.
Arbil provincial Governor Nozad Hadi confirmed the death toll and blamed IS jihadists, which Iraqi Kurdish forces are battling in both Iraq and neighbouring Syria.
A crowd of onlookers gathered at the site of the blast, which shattered car windows, scarred vehicles with shrapnel and left glass and debris scattered across the blood-stained street.
The bombing is the worst attack on Arbil since September 29, 2013, when militants struck the headquarters of the asayesh security forces, killing seven people and wounding more than 60.
French Senator Bruno Retailleau, who was at the provincial headquarters minutes before the blast, said that, "when you are visiting Arbil, there is absolutely no sense of danger."
"Retroactively, it's chilling," Retailleau, who was heading a delegation that delivered 10 tonnes of aid for displaced Iraqis, told AFP.
Iraq's three-province autonomous Kurdish region is generally spared the rampant violence plaguing other parts of the country.
There was no immediate claim of responsibility for the Wednesday attack, which rocked a usually crowded area close to the city's main landmark, Arbil's UNESCO-listed citadel.
But suicide bombings are usually carried out by Sunni extremists in Iraq, including a series of blasts claimed by IS in recent weeks.
Kurdish security forces are battling IS, which spearheaded an offensive that has overrun large areas of Iraq since June, making the region a more prominent target for militants.
Hundreds of thousands of people have been displaced from Arab-majority areas of Iraq to Kurdistan by the IS-led violence and earlier unrest this year.
Iraqi Vice President Osama al-Nujaifi, a Sunni Arab, Wednesday called on "citizens, especially those displaced to Arbil, to cooperate with the security services and help them in responding to the terrorist groups."
The initial jihadist onslaught swept federal security forces aside in the north, allowing the Kurds to take control of a swathe of disputed territory that they want to incorporate into their autonomous region over Baghdad's objections.
But IS turned its attention to the north again in August, launching a renewed drive that pushed Kurdish forces back towards Arbil, helping to spark a US-led campaign of air strikes that has since been expanded to Syria.
Backed by the strikes, Kurdish troops have managed to regain some areas seized by IS, as have federal forces backed by pro-government fighters.
But significant territory, including three major cities, remain in the hands of the militants.