The United States on Wednesday condemned a suicide bombing by Islamic State extremists in the usually safe Kurdish region of Iraq that killed at least four people and left more than two dozen injured.

"The United States strongly condemns the continued terrorist attacks in Iraq, including the suicide car bomb attacks today in Basrah and the Iraqi Kurdistan Region in front of the Arbil Provincial Council Building that took a number of innocent lives," the US State Department said in a statement.

"We extend our condolences to the families of the victims and hope for a rapid recovery for those who were injured," the US statement said.

"The Iraqi people are determined to stand against the violence and horrific ideology of the Islamic State of Iraq and the Levant (ISIL)," the US government said, using an alternate acronym for IS.

A bomber in an explosives-rigged vehicle hit the main checkpoint on the way to the provincial government headquarters in the northern city just before noon.

Two of the four killed were police, said officials who put the number of injured at 29.

The blast shattered car windows, scarred vehicles with shrapnel and left glass and debris scattered across the blood-stained street.

Iraq's three-province autonomous Kurdish region is generally spared the rampant violence plaguing other parts of the country.

Officials said the bombing is the worst attack on Arbil since September 29, 2013, when militants struck security force headquarters, killing seven people and wounding more than 60.

France identifies second national in IS execution video
Paris (AFP) Nov 19, 2014 - France on Wednesday identified a second national who appeared unmasked in a grisly Islamic State execution video and announced it was sending more jets to the region to step up air strikes.

French Defence Minister Jean-Yves Le Drian announced that six Mirage fighter jets would be sent to Jordan in December to boost air forces in their campaign against the jihadists.

He said French aircraft in Iraq had pummelled trenches used by IS fighters around the northern Iraqi city of Kirkuk on Tuesday night.

Currently France is using nine Rafale jets based in the more distant United Arab Emirates as part of a US-led international campaign to provide air support to Iraqi and Kurdish forces fighting the group.

Meanwhile, Nozad Hadi, the governor of Arbil, the capital of Iraq's Kurdistan region, blamed IS jihadists for a suicide car bombing which left four dead on Wednesday.

As France planned to step up its campaign abroad, at home it was reeling from the news that two of its nationals were among the jihadists seen in this weekend's IS video featuring the execution of 18 Syrian prisoners and US aid worker Peter Kassig.

IS has carried out widespread atrocities since seizing control of large parts of Iraq and Syria, executing five Western hostages and hundreds of locals.

Several of the jihadists appeared unmasked in the latest execution video and one foreigner, 22-year-old Maxime Hauchard from Normandy in northern France, was quickly identified by French prosecutors.

He is one of several young French nationals from a middle-class, atheist or Catholic background to have converted to radical Islam and gone to fight in Syria, making a profile of potential jihadists nearly impossible to pin down, experts say.

French prosecutors on Wednesday said there was "precise and consistent evidence" that a second national in the video was 22-year-old Mickael Dos Santos from an eastern Paris suburb, who goes by the name Abu Uthman.

Three more young French jihadists appeared in another video posted by IS on Wednesday. The footage shows the men burning their passports in front of the camera and calling on compatriots to stage attacks in France. They can also be seen carrying kalashnikovs.

- Some 50 French fighters killed -

Dos Santos, of Portuguese origin but born in the French riverside town of Champigny-sur-Marne, is believed to have left for Syria in the autumn of 2013.

French intelligence was made aware of him after he published an online video in October calling for "all brothers living in France" to "kill any civilian" in retaliation for air strikes carried out by Paris against IS in Iraq.

He was part of a network of radical young men in his neighbourhood, several of whom have also travelled to fight in the Middle East, a government source said.

"The man concerned is known for his terrorist involvement in Syria and his violent behaviour shown on social networks," French Prime Minister Manuel Valls said, without confirming his identity.

French authorities estimate around 1,000 nationals have taken part in the conflict, with 375 currently in the country.

Valls said "close to 50" French citizens had been killed in Iraq and Syria.

"So we know the dangers and, sadly, we are not surprised to learn that French citizens or residents of France are found at the heart of these cells and taking part in this barbarity," he added.

- 'Brainwashed' -

Thousands of foreign fighters have flocked to join IS in Iraq and Syria, and experts say they are often among the most violent and brutal of the jihadists.

A British-accented militant nicknamed "Jihadi John" has been at the centre of previous IS beheading videos and appeared again in Sunday's recording.

Other known foreign fighters are believed to have appeared in the video, including an Australian and a Dane.

A Belgian newspaper reported that one of the men featured in the video looked like Abdelmajid Gharmaoui, who is currently on trial in his absence in Belgium for membership of a jihadist group.

But authorities in Belgium said they had ruled out the presence of any Belgian nationals in the video.

French President Francois Hollande, on a visit to Australia, said the issue of foreign fighters and how they were being "brainwashed" was a major concern.

"They could be from any background, from any ethnic origin -- but they can easily be brainwashed into becoming converts, and this is a very important matter," he said.

"We must be vigilant, and we must be strong."