AFP

France carried out its first air strike against the Islamic State group in Iraq Friday, boosting U.S.-led efforts to unite the world against the growing threat posed by the jihadists.

More than a decade after Paris famously refused to back the invasion of Iraq, France became the first nation to join the U.S. campaign of air strikes in the war-torn country.

"This morning at 9:40, our Rafale planes carried out a first strike against a logistics depot of the terrorist organization (IS)," President Francois Hollande said.

His office said the target was in northeastern Iraq, without specifying exactly where, only adding: "The objective was hit and completely destroyed."

French defense ministry sources said two jets dropped laser-guided GBU-12 bombs in the Mosul area.

Kurdish military spokesman Halgord Hekmat identified the location as Tal Mus, between the city of Mosul and Zumar.

"We are very happy that France started its raids," he told AFP.

France, as well as Britain, had already sent aircraft into Iraq's skies for surveillance missions but Friday's strike was its first against the jihadists.

U.S. aircraft have carried out more than 170 strikes since August 8 but President Barack Obama has been keen to build a broad international coalition.

The bombing campaign was launched to protect Iraqi Kurdistan from advancing jihadists and attempt to help the autonomous region's troops retake the ground they lost.

Jihadists who had already controlled large swathes of land in neighboring Syria led a militant offensive that took the city of Mosul, Iraq's second largest, on June 10 and then swept through much of the Sunni heartland.

In a second push in August, they dealt Iraq's Kurdish peshmerga forces a string of military defeats and attacked various minority groups, demolished heritage sites and displaced hundreds of thousands of people.

Footage of the beheading of two U.S. journalists and a British aid worker in Syria sparked international outrage and spurred calls for tougher action against what is widely regarded as the most violent and powerful organization in modern jihad.

Despite broad domestic support for a tougher stance, Obama has vowed not to send "boots on the ground", fearful of dragging U.S. forces back into the Iraqi quagmire only three years after pulling them out.

The U.S. leader has instead pledged to support Kurdish and Iraqi federal forces by offering air support and arms, as well as targeting intelligence and training.

On Thursday Congress backed his plan to arm rebels to take on IS in conjunction with air strikes Obama has pledged to carry out inside Syria.

"These terrorists thought they could frighten us, or intimidate us, or cause us to shrink from the world," he said, after a rare moment of bipartisanship in the House.

"But today they're learning the same hard lesson of petty tyrants and terrorists who have gone before."

Hitting back in the propaganda war, the jihadists posted their latest video of a Western hostage, British journalist John Cantlie, in an orange jumpsuit.

In the footage, Cantlie promises to reveal in a series of programs the "truth" about the jihadist group and appears to be under no immediate threat of being executed.

Some analysts argued the tone of the video revealed IS was afraid of Western air strikes and was trying to convey a less barbaric image of an organization not incapable of reasonable behavior.

As security forces and militia, backed by expanding air strikes, battled to regain ground from IS and allied groups, Iraq was rocked by a series of bombings.

In a Shiite-dominated areas of northern Baghdad, militants blew up two car bombs and lobbed mortar rounds late Thursday, killing at least 28 people in what some said was an attempt to target an army intelligence base where senior IS members are held.

Three bombings in and near the capital on Friday killed at least 14 people, while a fourth in the northern city of Kirkuk killed eight more, officials said.

In Syria, IS fighters were closing in on the country's third-largest Kurdish town of Ain al-Arab, or Kobane, on the Turkish border, cutting off its Kurdish defenders, a monitor said.

"IS fighters have seized at least 21 villages around Kobane," said Rami Abdel Rahman of the Syrian Observatory for Human Rights. "The IS is using heavy weaponry, its artillery and tanks."

The town is one of three Kurdish majority areas where Kurdish nationalists have proclaimed self-rule and its capture would give the jihadists control of a long stretch of the Turkish border.

Syria's exiled opposition National Coalition warned of "the danger of a massacre" in the area, where Kurdish militia have doggedly resisted the jihadists.

Washington estimates IS has 20,000 to 31,500 fighters and there are concerns that returning jihadists could carry out attacks in Western countries.

According to the latest official statistics, the largest contingent of Western jihadists comes from France.