Story highlights Gen. Lloyd Austin heads the United States Central Command

Austin said he has seen evidence the U.S.-led coalition is gaining upper hand against ISIS

General wants Turkey to grant coalition more access, over-flight rights

The top U.S. military commander in the fight against ISIS said airstrikes are working to erode the terror group's capabilities and warned militants that the U.S. military is listening to them.

Army Gen. Lloyd Austin, who heads the U.S. Central Command, made those remarks at an event Thursday with the Atlantic Council, which was moderated by CNN anchor and Chief Washington Correspondent Jake Tapper.

"I'm confident we're having the desired effects," Austin said of airstrikes in Syria and Iraq aimed at ISIS.

Photos: U.S. military assets used against ISIS Photos: U.S. military assets used against ISIS U.S. Army Apache helicopters, like the one pictured here, have been used to support Iraqi troops in their fight against ISIS. Click through the gallery to see what other military assets the Pentagon has put into the ISIS battle. Hide Caption 1 of 11 Photos: U.S. military assets used against ISIS The workhorses of the American fighter fleet, F-16s, have been used in dozens of strikes against ISIS. F-16s can travel 1,500 mph, or Mach 2, at altitude. Hide Caption 2 of 11 Photos: U.S. military assets used against ISIS A F-15E Strike Eagle from the 391st Fighter Squadron takes off in July during a mission at Joint Base Pearl Harbor-Hickam in Hawaii. The F-15E Strike Eagle can carry more than 23,000 pounds of payload for air-to-ground and air-to-air combat. The plane has been in the Air Force inventory for three decades and is expected to be operational until at least 2035. Hide Caption 3 of 11 Photos: U.S. military assets used against ISIS The A-10 Thunderbolt II, also known as the Warthog, joined the fight against ISIS in late 2014. The jets are specially designed for close air support of ground forces. Hide Caption 4 of 11 Photos: U.S. military assets used against ISIS U.S. Air Force F-22 Raptors saw their first combat during strikes on ISIS targets in Syria, the Pentagon said. The single-seat, twin-engine stealth fighter has a top speed of almost 1,500 mph. Here, a Raptor performs during the Australian International Airshow in March 2013. Hide Caption 5 of 11 Photos: U.S. military assets used against ISIS The Air Force's B-1B Lancer bomber was introduced in the 1980s to carry out nuclear missions. The plane was adapted for conventional weapons missions in the 1990s and has flown in combat over Iraq, Kosovo and Afghanistan. Here a B-1B flies above Iraq in support of Operation New Dawn in February 2011. Hide Caption 6 of 11 Photos: U.S. military assets used against ISIS F/A-18 jets and other aircraft used in strikes against ISIS have been launched from Navy carriers, including the the USS George H.W. Bush, a 103,600-ton aircraft carrier seen here in April as it transits the Strait of Hormuz. Hide Caption 7 of 11 Photos: U.S. military assets used against ISIS EA-6B Prowlers are among the U.S. aircraft that took off from the USS George H.W. Bush during attacks on ISIS. The Prowler is used to support attack aircraft by jamming enemy radar and communications and obtaining tactical intelligence. Here, a Prowler -- seen at bottom -- flies in formation with an E-2C Hawkeye in June 2004. Hide Caption 8 of 11 Photos: U.S. military assets used against ISIS The guided-missile cruiser USS Philippine Sea, operating in international waters in the North Arabian Gulf, launched Tomahawk cruise missiles used against ISIS targets in Syria in some of the initial strikes on ISIS. The ship has a displacement of 9,589 tons and carries a crew of 370. Hide Caption 9 of 11 Photos: U.S. military assets used against ISIS On September 22, 2014, the United States fired 47 Tomahawk missiles against targets in Syria. Tomahawks are long-range subsonic cruise missiles used to take out high-value or heavily defended land targets. They were first used in Operation Desert Storm in 1991. Here, the U.S. Navy guided-missile destroyer USS Barry (DDG 52) launches a Tomahawk cruise missile in 2011. Hide Caption 10 of 11 Photos: U.S. military assets used against ISIS The guided-missile destroyer USS Arleigh Burke, operating in the Red Sea, launched Tomahawk cruise missiles against ISIS targets in the first of three waves of attacks that began on September 22. The ship has a displacement of 8,373 tons and carries a crew of 370. It is part of the U.S. 5th Fleet. Hide Caption 11 of 11

"What we want to do is take away the enemies' ability to command and control, his ability to sustain himself, his ability to project combat power and his ability to move forces back and forth across the Iraq/Syria border."

Latest strikes target Khorasan group

Austin said coalition airstrikes on Wednesday were focused on the Khorasan group. Senior military officials told CNN one of the targets was French bomb-maker David Drugeon. Austin said the military was still assessing the impact of those strikes and would not say whether or not Drugeon was killed.

Army Gen. Lloyd Austin speaks with CNN's Jake Tapper.

But, he noted that "any time we can take their leadership out that's a good thing."

Austin said there is evidence that the U.S.-led coalition is gaining the upper hand against ISIS.

"They are afraid to congregate in any sizable formation. They know if we can see them, we're going to engage them and we're going to hit what we're aiming at."

We can hear you...

Austin also said the strikes have significantly degraded the group's ability to communicate and added the coalition was able to listen in on ISIS communications.

"As we listen to them, we know that the impact of the precision strikes is demoralizing to them."

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The general responded to questions about ISIS militants getting access to warplanes, after the militants were seen on their social media channels with a number of captured aircraft.

"I don't think that's currently a significant threat. I know I have some fighter pilots who are hopeful that happens," he said, drawing chuckles from the crowd.

ISIS still has the capability to continue in the fight, the general said, despite what he pointed to as successes from the coalition side.

"I think the question is how soon can we get the Iraqi military up to speed to do what they need to do to hold those gains."

Austin acknowledged the ISIS propaganda effort was having a major impact in recruitment for the group."They really understand the value of dominating the media space. I think they're about as good as I've seen."

He said their numbers of committed fighters was likely between 9,000-17,000, a figure much lower than previous U.S. estimates.

Austin echoed other comments from military leaders that the fight against ISIS will be years long but said, "I don't see it as decades. I see it as years."

'Turkey has skin in the game'

One member of the coalition has caused a certain amount of controversy. Turkey has limited use of its airspace and military bases despite pledging to help in the effort.

"Turkey has skin in the game here, obviously. It's got a set of concerns and we need to be mindful of that," Austin said, adding that the coalition would "get it done" with or without more support from the Turks.

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"The more access and over-flight rights we can get, the better off we'll be."

Tapper asked about speculation ISIS was receiving financing from U.S. ally Qatar, and how successful the coalition had been at stopping the outside funding of the group.

"I think some things have been done but I think most folks in U.S. government will tell you, there's a lot more work that can be done and needs to be done," Austin said.

The event was open to the media but cameras were prohibited from filming the session and a previously scheduled live stream of the event by the Atlantic Council was canceled at the request of CENTCOM.

CENTCOM said it agreed to the event under the auspices that it was a "scholarly discussion." CNN and other broadcast outlets protested the decision.