A top anti-terror expert is urging Western leaders to act now in a coordinated all-out campaign to crush the Islamic State, saying the group's military muscle has been significantly degraded over the last few months.

Dr. Afzal Ashraf, a researcher at the Royal United Services Institute think tank, told the London Express on Monday that "Russian airstrikes, unruly leadership and numerous defections" have destabilised the terror organisation to the point that it would not be difficult anymore to neutralise it.

"This mythical state will disappear in a matter of hours once the international community decides to act. It won't take very long at all to drive them if not out of all of Iraq or Syria, then certainly the majority of their territories,'' he said, according to WND.

"They will hide in towns, but I would say do not follow them as they would use innocent civilians as human shields. Leave them in the isolated settlements, and they will soon lose control," Dr. Ashraf said.

Dr. Ashraf's call comes as Russian air attacks have reportedly blown up at least nine ISIS posts, demolishing a vital command centre and likely killing dozens of jihadis, as Moscow appears to be preparing for a ground offensive to take control of the city of Raqqa, the ISIS capital, said WND.

But according to Retired US Army Lt. Gen. William G. "Jerry" Boykin, former deputy undersecretary of defense for intelligence from 2002 to 2007, "ISIS is an ideology that cannot be defeated only through kinetic solutions.''

"It is not credible in my view. ISIS is well armed because of all the US equipment that the Iraqis have left behind. ISIS is also well-funded because of the oil (dollars) and the bank robberies and extortion they have been involved in. That allows them to buy tribal leaders and to purchase modern communications and materiel," he told WND.

The US has led a coalition of airstrikes against ISIS and is reportedly preparing to open a major front in Raqqa, the New York Times reported.

President Obama has also reportedly ordered the Pentagon to provide weapons to Syrian rebel groups as part of efforts to fight the terror faction.

Russian President Vladimir Putin, on the other hand, is set to dispatch 150,000 troops to Syria to wipe out ISIS despite criticisms from the US-led coalition already fighting in the area, WND said.

Earlier, Obama warned Russian President Vladimir Putin that Russia risked being sucked into a "quagmire" if he continuous to act on his own. He also said that the Russian airstrikes will only help increase local support for ISIS.