A top US official has said that Iraqi troops will begin a major ground offensive against the Islamic State of Iraq and Levant (ISIL) group in the coming weeks.

Retired General John Allen, the US co-ordinator for the anti-ISIL coalition of Western and Arab countries, said on Sunday that the offensive would be launched "in the weeks ahead".

"When the Iraqi forces begin the ground campaign to take back Iraq, the coalition will provide major firepower associated with that. John Allen, US co-ordinator for the anti-ISIL coalition

"When the Iraqi forces begin the ground campaign to take back Iraq, the coalition will provide major firepower associated with that," he told Jordan's official Petra news agency.

The ISIL group took control of vast swathes of Syrian territory and areas north and west of the Iraqi capital last June, with the Iraqi military fleeing their onslaught.

Al Jazeera's Jane Arraf, reporting from Baghdad, said: "Iraqi officials have been eager to begin this offensive, particularly in Mosul.

“But the coalition, primarily the US, has not been quite so keen as they have made a point, General Allen included, that before grounds troops go in to take Mosul they need everything to be ready.

"That includes training of Iraqi forces and plans for what comes after - including the training of the police force as well as things like humanitarian assistance and reconstruction.

"All of that is a long-term effort but General Allen's comments indicate that they are on board for supporting the Iraqis at the beginning of a major ground offensive.

"The US is now training soldiers as well as forces and special security forces.

"They [the US] are not on the ground and they don't have the authority to do that, but there are other coalition partners that are believed to have Special Forces out there with the Iraqis."

Coalition gains

In recent weeks, the Iraqi army seems to be regaining ground with support from US-led air strikes that began in August.

Jordan announced it has carried out dozens of strikes against the armed group since Thursday, as it sought to avenge a pilot burned alive by the group.

Iraqi forces have already carried out operations near Baghdad and in Diyala and Salaheddin provinces north of the capital.

The ISIL fighters were stopped short of Baghdad in June and have since been pushed back.

Speaking at a conference in the German city of Munich, US Secretary of State John Kerry said that the air campaign was helping ground forces to win back territory and depriving the fighters of key funds.

There have been 2,000 air strikes on ISIL so far, Kerry said. They have helped ground forces to retake some 700 square kilometres of territory from the armed group, or "one-fifth of the area they had in their control", he said.

Kerry did not specify whether the recaptured territory was in Iraq or Syria.