Monday Speculation. ISIS claims to have shot down a Russian airliner...what will the response be?

By now you've heard the claims by ISIS of having shot down a Russian airliner.  The response by US intel community is interesting.  They state that at this time there is no evidence that they plane was shot down.

Clearly we or one of our allies (looking at you Israel) have full visibility on what happened but everyone is remaining silent.

That leads me to believe that the airliner PROBABLY was shot down and the pronouncement by our intel community is possibly a gambit to freeze the Russians.  Which is worse?  Admitting that the ISIS savages shot down an airliner or remaining quiet and allow it to be assumed that the plane suffered a mid-air catastrophe?

I don't see the Russians taking the laid out "off ramp" which means its might be time to think about their response.  I only see a couple of likely possibilities...

*  The Russians provide evidence that the plane was shot down and then launch a series of devastating air strikes against ISIS and other rebel groups...

*  The Russians go the US route and employ their large special forces against those responsible....

*  They do nothing and let events unfold...

Personally I'm betting on more aircraft being deployed to the region and stepped up air strikes.