New Rescue Mission for ISIS Hostages Difficult, Still Possible: Experts

— -- A second rescue operation to free the American hostages held by the terror group ISIS is still a possibility, former military sources said, even though a secret mission into Syria in July may have tipped America’s hand.

“There’s always going to be the option of conducting another raid or another attempt,” retired Green Beret commander Lt. Col. Jim Gavrilis told ABC News. “We may have lost some strategic surprise, but tactical surprise is still possible. They don’t know when we’re going to strike or where we’re going to strike.”

Senior U.S. officials told ABC News last month that a “substantial and complex” rescue operation, which involved sneaking several dozen commandos into the heart of Syria, had been launched weeks before. The mission went “flawlessly,” except that there were no hostages at the location to rescue, Defense Secretary Chuck Hagel told reporters a day after ABC News and others reported the operation.

Some involved in the first rescue attempt were “crushed” when the American forces arrived at the site only to discover a “dry hole,” according to an intelligence official. The mission, had it been a success, could have saved the lives of American journalists James Foley and Steven Sotloff, believed to have been executed later on camera by a masked ISIS militant.

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Others within the special operations community were aghast the White House confirmed on the record that special mission units had tried to rescue the hostages in Syria, feeling it potentially compromised a future mission.

A former Army special operations soldier said public information about the mission – including the detail that the U.S. force was brought in by helicopter -- “severely limits options now for those units tasked with conducting the hostage rescue missions.”

“The ability to infiltrate and have surprise, speed and violence of action on our side is determined in part by the methods by which we can infiltrate, making the way we did it before much more likely to be compromised… The bad guys would probably have a plan now by which to defend against a helo [helicopter] assault,” he said.

Still, the former special operator said a second attempt “isn't out of the question… We’ll just probably have fewer options on infiltration platforms.”

Beyond a hostage rescue, other special missions could be opening up, according to U.S. officials who said that top ISIS leaders appear to be using encrypted communications to avoid being detected, but that surveillance at ISIS command centers has begun to produce a few possible targets.

“If the U.S. … has a drone or fixed wing aircraft with the ability to strike an ISIS target, especially a senior leader, they’ll do it now,” said Seth Jones, a terrorism expert at the RAND Corporation.

In recent days top U.S. officials have issued strong words for ISIS – including Vice President Joe Biden saying the U.S. will follow the terror group to “the gates of hell” – and Thursday the White House Deputy National Security Advisor Ben Rhodes told ABC News’ Jon Karl the administration is “absolutely” considering airstrikes in Syria to target ISIS, in addition to the dozens already launched in Iraq.