A suicide bombing hit the usually secure Iraqi Kurdish capital of Erbil on Wednesday, killing at least four people in the first major attack on the city for over a year.

An unidentified assailant attempted to drive an explosive-filled car into the city governate building around midday local time, but the vehicle detonated prematurely when guards fired on it, according to local media.

Two members of the security forces and two civilians were killed and 22 others injured in the blast, health ministry sources told Kurdish media outlet Rudaw.

Video via Youtube/Rudaw Kurdish

The site of the attack was quickly sealed off by security forces and by 1530 local time, charred cars and other debris was already being cleared.

No one has yet claimed responsibility for the bombing, but Erbil governor Nawzad Hadi told Rudaw that he suspected the jihadist organization known as the Islamic State (IS).Fighters affiliated with the extremist group seized control of a large section of northern Iraq in June, and in August advanced to less than 20 miles from Erbil before a Kurdish counterattack backed by American airstrikes halted their progress.

Video via YouTube/KurdistanTV

A suicide bombing hit the usually secure Iraqi Kurdish capital of Erbil on Wednesday, killing at least four people in the first major attack on the city for over a year.

An unidentified assailant attempted to drive an explosive-filled car into the city governate building around midday local time, but the vehicle detonated prematurely when guards fired on it, officials told local media.

"This car just came our direction and boom, in the air," Nezaan Hassan Mahmoud, 19, who was sitting at the side of the road with some friends in the aftermath of the bombing, told VICE News.

Two members of the security forces and two civilians were killed and 22 others injured in the blast, health ministry sources told Kurdish media outlet Rudaw.

The site of the attack was blood-stained and strewn with debris, but security forces quickly sealed off the area and by 3.30pm local time (12.30pm GMT), burnt out cars were being towed away and streets washed down.

No one has yet claimed responsibility for the bombing, but Erbil governor Nawzad Hadi told Rudaw that he suspected the jihadist organization known as the Islamic State (IS). Fighters affiliated with the extremist group seized control of a large section of northern Iraq in June, and in August advanced to less than 20 miles from Erbil before a Kurdish counterattack backed by American airstrikes halted their progress.

Abdullah, 42, a member of the security forces guarding the scene of the attack who declined to give his surname, told VICE News that he was convinced IS was to blame. "We know it is the militants of IS because we are now officially at war with them," he said, adding that that Kurdish forces had arrested at least 10 non-Iraqis, which he described as "foreign Kurds, who are here in Erbil for IS".

Suspicion of all foreigners around the scene was evidently high, however. A group of around 20 members of the security forces at the site of the bombing aggressively detained, held and questioned VICE News before claiming their actions were "protection."

IS is now facing off against Kurdish peshmerga forces along a frontline stretching more than 600 miles and has repeatedly threatened to launch attacks in territory controlled by Iraq's Kurdish Regional Government. However, unlike the central capital of Baghdad, which is regularly rocked by large car bomb blasts, Erbil, along with much of the rest of Iraqi Kurdistan has remained relatively stable. The last major terrorist incident in the KRG capital took place on September 29, 2013 when coordinated suicide and car bomb blasts hit the local security services, known as Asayish, killing seven and wounding dozens more.

Some residents feared that the latest attack might herald further violence in the previously peaceful enclave. "Allah, please protect Kurdistan, it is our second home after we left our houses behind," Ahmed Khatab, 27, who fled Tikrit when IS seized the city, told VICE News.

Others remained defiant, however. Anwar Tawfiq Kader, 53 told VICE News that even if violence intensified, he wouldn't leave his home. "We fought for this land for too long, I will never leave. I am staying here to defend the city until I die... We, the Kurds, will stand up against all the terrorists, all these animals. I am furious because of the martyrs, but they will not break me."

The bombing came as Kurdish forces launched new offensives on IS positions in Iraq. In Diyala, peshmerga forces launched an operation alongside Iraqi troops to take back the towns of Saadiya and Jalawla, Jaber Yawer, a spokesman told the Associated Press. Meanwhile in Kirkuk province, peshmerga backed by US-led air support battled to retake ground near Kharbaroot, 22 miles west of Kirkuk city.

However, KRG president Masoud Barzani said that requests for heavy weapons from the US-led anti-IS coalition have not yet been completely met. In an interview with France 24, Barzani said that the peshmerga would need a greater quantity of more sophisticated weapons in order to defeat their extremist foes. "The heavy weapons systems that we need, especially in terms of the quality and quantity, for example the APCs (armoured personnel carriers), the helicopters, the artillery we need for a decisive war against them - we have not received these types of weapons."