IS jihadists will be 'very seriously dented' by end of 2016: John Kerry

Davos: US Secretary of State John Kerry on Friday said the US-led coalition bombing Islamic State strongholds in Syria and Iraq will reach their goal of "seriously denting" the group by the end of 2016.

"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 and Raqqa will be achieved," Kerry told reporters on the sidelines of the World Economic Forum in Davos, using an alternative name for Islamic State (IS).

"We are on track, we are doing serious damage to Daesh on Friday. They lost 35 per cent, 40 per cent of their territory that they control, 40 per cent in Iraq, 20 per cent to 30 percent total," he said.

The coalition includes Gulf states and Britain. Russian and French jets have also been pounding IS positions.

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

"(Defence Secretary Ashton Carter) was just in Paris meeting with coalition members, they are all committed," Kerry said.

The US has called on allies to contribute special forces as a key part of their effort to bolster coalition forces fighting the jihadist group.