The United States has halted the course of the Islamic State group, President Barack Obama said in remarks broadcast Friday, calling for a stepped up drive to "completely decapitate" the militants' operations.

The ABC News interview was recorded Thursday at the White House, hours after the start of a major operation by Iraqi Kurdish forces, backed by US-led strikes, to drive IS out of the northern town of Sinjar.

"I don't think they're gaining strength," said Obama. "From the start, our goal has been first to contain, and we have contained them. They have not gained ground in Iraq."

"And in Syria -- they'll come in, they'll leave. But you don't see this systematic march by ISIL across the terrain," he said, using an alternate acronym for IS.

Obama gave the interview before news broke of a US air strike in Syria targeting "Jihadi John," a masked British militant who appeared in a string of graphic execution videos.

IS has seized large chunks of territory in Iraq and Syria.

"What we have not yet been able to do is to completely decapitate their command and control structures. We've made some progress in trying to reduce the flow of foreign fighters," Obama said.

"Part of our goal has to be to recruit more effective Sunni partners in Iraq to really go on offense rather than simply engage in defense."

The president warned that regional strife will persist "until we get the Syria political situation resolved."

"Until Assad is no longer a lightning rod for Sunnis in Syria and that entire region is no longer a proxy war for Shia-Sunni conflict, we're going to continue to have problems," he said.

"I would distinguish between making sure that the place is perfect -- that's not going to happen anytime soon -- with making sure that ISIL continues to shrink in its scope of operations until it no longer poses the kind of threat that it does."

Key developments in war against IS
Baghdad (AFP) Nov 13, 2015 - The main developments in the war against the Islamic State in Syria and Iraq since August 2014, after the jihadist group lost Iraq's Sinjar on Friday and a key supply route between the two countries:

- First air strikes -

On August 8, 2014, US jets strike IS positions in northern Iraq in response to an appeal from Baghdad, in the first American military operation in the country since troops withdrew in late 2011.

Already entrenched in neighbouring Syria, IS seized swathes of Iraqi territory in a lighting offensive launched in June 2014 and marked by the frantic retreat of security forces.

Particularly exposed are Iraqi Kurdistan and Christian and Yazidi minorities.

On September 5, US President Barack Obama vows to build "a broad, international coalition" to defeat IS.

On September 23, the US and its Arab allies launch air strikes on IS in Syria.

- IS driven out of Syria's Kobane -

On January 26, 2015, IS is driven out of the Syrian border town of Kobane after more than four months of fighting led by Kurdish forces backed by coalition air strikes.

On the same day, an Iraqi military official announces that the eastern province of Diyala has been liberated.

- Iraq's Tikrit retaken -

On March 31, Baghdad announces the "liberation" of Tikrit, 160 kilometres (100 miles) north of Baghdad. Government forces backed by Shiite militias retake Tikrit after a vast operation launched on March 2 against the IS, which had controlled it for nearly 10 months.

But in May, the IS takes Iraqi provincial capital Ramadi, and then Syria's famed ancient city of Palmyra, a UNESCO World Heritage site.

- IS driven from border town -

On June 16, Kurdish militia backed by Syrian rebel force and coalition air strikes seize the key Syrian border town with Turkey of Tal Abyad from IS, which had occupied it for more than a year.

Tal Abyad was one of two main transit points on a key supply route to de facto IS capital Raqa.

- Turkey declares war on jihadists -

On July 24, Turkish warplanes bomb IS positions inside Syria for the first time in a dramatic toughening of Ankara's stance.

The Turkish raids are largely aimed at positions of the Kurdistan Workers Party in Iraq and Syria.

Turkey gives Washington the green light for US warplanes to fly operations over Syria from its key southeastern air base of Incirlik.

- First French strikes in Syria -

On September 27, France carries out its first air strikes against the IS in Syria.

France has been part of the US-led coalition bombarding IS targets in Iraq since September 2014.

- Russia intervenes in Syria -

On September 30, Russia launches air strikes in Syria, in what it says is a campaign against "terrorists" to help the Damascus regime, of which it is an ally.

Washington accuses Moscow of also targeting Syrian rebels.

On November 10, Syria's army breaks a more than year-long jihadist siege of a military air base in the country's north, scoring its first major breakthrough since Russia's air campaign began.

- Iraq's Sinjar retaken -

On November 13, Iraqi Kurds announce the "liberation" of Sinjar from the IS in an assault backed by US-led strikes that cut a key jihadist supply line with Syria.

On the other side of the border, a coalition of Arab and Kurdish fighters eject IS from the village of Al-Hol on the supply route.