The jihadist group Islamic State is "growing like crazy," with its international branches spreading into North and West Africa, the Arabian Peninsula, Afghanistan and into the Far East, a top US official was quoted as saying.

Speaking on "Meet the Press" on Sunday, NBC's Richard Engel said the US official he talked to, which he did not name, also told him that "ISIS has expanded far more quickly and extensively than al-Qaeda ever did" despite the continuing coalition air strikes and ground action taken by pro-coalition forces.

"The US has been bombing ISIS for nearly a year, and finally got access to bases here in southern Turkey, bringing jets and drones far closer to their targets, a huge tactical gain. But ISIS doesn't seem to be shrinking," Engel said.

He said the US strategy's three pillars—retraining the Iraqi army, training Syrian rebels, and airstrikes— "are all shaky."

"Retraining the Iraqi Army. It's been slow, and Iran often called the shots. Training Syrian rebels. But so far, only a handful are ready to fight, and many of them have already been kidnapped. And finally, the airstrikes, which are killing ISIS fighters and leaders, but who are then replaced," he said.

He said the US military, led by its Special Operations unit, is having a major policy review with the aim of crafting a new global strategy to combat ISIS.

ISIS destroys another temple, detains dozens

ISIS is not only killing people but also destroying historical sites.

According to CBS News, ISIS has set off an explosion that damaged the Bel Temple in Palmyra, Syria that left only the wall of the temple standing.

ISIS militants also detained at least 70 residents, tying dozens of them to streetlights and tagging them as dissidents.

The ISIS action was prompted by a rare street demonstration in Rutbah, Anbar province, on Saturday when hundreds of residents came out to protest the ISIS execution of a local resident, reports said.

The resident was a civil servant identified as Munir al-Kobeisi who allegedly killed an ISIS member due to an ongoing feud between two warring clans.