PARIS: U.S. Secretary of State John Kerry Thursday said ISIS would be "very seriously" weakened in Syria and Iraq this year, as France announced that some 22,000 extremists have been killed by the U.S.-led coalition.

Airstrikes by the alliance that includes Gulf states, France and Britain have been pounding ISIS positions since August 2014, with Washington claiming major gains against the extremists.

"I think that by the end of 2016, our goal of very seriously denting Daesh in Iraq and Syria and of trying to have an impact on Mosul (in Iraq) and Raqa (in Syria) will be achieved," Kerry told reporters on the sidelines of the World Economic Forum in Davos, using an alternative name for ISIS.

"We are on track, we are doing serious damage to Daesh today," he said.

The Pentagon estimates that ISIS has lost 20-30 percent of the total territory they were in control of in Iraq and Syria, including up to 40 percent in Iraq alone.

Kerry said he would meet the foreign ministers of 24 coalition nations in Rome on Feb. 2 to discuss strategy and possible "additional commitments".

The U.S. has called on allies to contribute special forces as a key part of the efforts to bolster coalition forces fighting the extremist group.

U.S. special forces are already directly engaged in pinpointing targets and launching raids against ISIS in both Syria and Iraq, U.S. Defense Secretary Ashton Carter said Thursday.

"These forces have already established contact with new forces that share our goals, (opening) new lines of communication to local, motivated and capable fighters, and new targets for airstrikes and strikes of all kinds," Carter said in Paris.

No nation is providing precise figures on how many of their special forces are operating in the region, but it has become increasingly clear that elite Western troops are providing more than training, and shifting towards more of a frontline role.

In Iraq, "we now have a specialized expeditionary targeting force in place that is preparing to work with the Iraqis to begin mounting sudden, long-range raids, going after ISIS fighters and commanders, killing or capturing them wherever we find them, along with other key targets," Carter said, using an alternative name for ISIS.

French President Francois Hollande said the anti-ISIS coalition would "accelerate" its airstrikes.

His comments followed a meeting by the defense ministers of seven countries in the coalition Wednesday, who said their strategy was to free the ISIS "power centers" of Raqa and Mosul.

"They also decided to reinforce support to Arab and Kurdish forces fighting Daesh on the ground," the French president said.

Around 22,000 extremists have been killed by the U.S.-led coalition fighting ISIS since mid-2014, France's own defence minister said Thursday.

"The figure given by the coalition... is about 22,000 dead since the start of operations in Iraq and Syria," Jean-Yves Le Drian told the France24 news channel, adding that the figure was "approximate".

- 'Perfect chaos' -

Meanwhile, the EU's counter-terrorism coordinator chief Gilles de Kerchove said ISIS' military losses in Syria and Iraq may prompt some of its leaders to relocate to strife-torn Libya where they would face less pressure.

"There, for the time being, it's the perfect chaos they like," he told AFP.

The anti-ISIS coalition's attacks have intensified since November's deadly extremist attacks in Paris, with oil sites among the main targets in a bid to cut the group's key revenue stream.

Le Drian said the group's finances were "beginning to dry up".

U.N.-brokered Syrian peace talks had been tentatively set for Monday in Geneva, despite disagreements over who will represent the opposition.

But the United Nations said the talks could be delayed by a few days.

"It is likely the 25th may slip by a few days for practical reasons," Jessy Chahine, a spokeswoman for U.N. Syria envoy Staffan de Mistura, told AFP in an email Thursday.