DUHOK, Iraq — Multiple suicide bombers struck the capital of Iraq’s semi-autonomous Kurdish region Sunday, killing six and injuring dozens of others, according to a security official. It was the first major attack to hit what is known as Iraqi Kurdistan in years, stunning residents of the normally peaceful region.

The complex attack occurred outside the headquarters of the Kurdish secret police, known as the Asayish, around 1:30 p.m. local time in Irbil, capital of the three-province Kurdish area, according to a statement from the Asayish.

A mini-bus drove to the building’s gate and detonated after coming under fire from guards. Then, four attackers on foot and strapped with explosives opened fire on guards, who returned fire, killing all of them, according to the security official. At least one blew himself up.

After emergency workers arrived, an ambulance packed with explosives drove to the gate and detonated, according to the Asayish statement. The Kurdistan regional government Health Ministry denied any of its ambulances were used.

Six people were killed and 62 injured, according to Kurdistan's health minister, and security officers and health workers were among the dead.

After the bombing, all roads into Irbil were closed as authorities searched for additional bombs. They advised those in the city to stay away from public places, major roads and government buildings.

Iraqi Kurdistan is an autonomous region bordering Turkey, Iran and Syria, with its own president, parliament, and army, known as the Peshmerga.

The Syrian civil war is raging just over the Kurdistan border, with Kurdish militias seeing heavy fighting against Islamist rebels, including the al-Qaida-linked al-Nusra Front and the Islamic State of Iraq and Syria, which has a long history of terrorist attacks in Iraq. More than 200,000 Syrian refugees have crossed into Iraq’s Kurdish provinces, and Iraqi Kurdish President Massoud Barzani has warned his military could intervene if Syrian Kurds are not protected.

Authorities would not say if they suspected the bombing was connected to Syria.

The attack comes just over a week after regional elections, which saw the ruling Kurdistan Democratic Party hold onto power. The border to Syria was closed for more than two weeks around the election, only re-opening Sunday.

Iraqi Kurdistan has long been considered the safest region of Iraq, garnering significant foreign investment and even some tourism. Benefitting from a U.S.-enforced no-fly zone after the first Gulf War and seeing almost no fighting during the most recent war in Iraq, it has been an oasis of stability, in stark contract to Baghdad and other areas of Iraq, which have been rocked by a spate of deadly attacks in recent weeks and have seen rising levels of violence over the past year.

Before Sunday, the last attack in Irbil was a truck bombing in 2007 that killed 15 people. That was the first major attack in the city since June 2005. The last major attack in Iraqi Kurdistan was a suicide bomb at a hotel in the city of Sulaymaniyah in 2008 that killed one person and injuring 29. Twitter: @Druzin_Stripes

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