(CNN) A senior US general has confirmed that the US has ended a classified CIA program to arm anti-Assad rebels in Syria.
Appearing at the Aspen Security Forum on Friday, General Raymond Thomas, head of US Special Operations Command, said the decision was not made to appease Russia which supports Assad.
"From at least what I know about that program and the decision to end it, absolutely not a sop to the Russians," Thomas said. "It was I think based on an assessment of the nature of the program, what we're trying to accomplish, the viability of it going forward and it was a tough tough decision."
John Brennan, who served as director of the CIA under President Barack Obama was also asked about the decision at Aspen by CNN's Elise Labott. He did not talk about the specifics of the program, but he said the anti-Assad rebels deserve US support.
Thomas went on to offer extended comments on a number of national security and military matters at Aspen.
On the fight against ISIS, Thomas made clear the US military understands President Donald Trump wants to do more than just defeat the terror group.
"The description of our mission is pretty clear. It is now to annihilate ISIS," he said. "We all got the message, in fact, we are pressing as hard as we can."
Commanders have pointed to efforts to isolate and kill foreign fighters so they cannot escape. Thomas estimated the coalition has killed 60,000 to 70,000 ISIS fighters, but the US coalition has not confirmed that number.
Thomas offered unusually candid public remarks for a US four-star general about the capabilities of Iraqi Kurds when they first began to fight ISIS in 2014.
"I was personally disappointed with the Peshmerga," he said. "Again I spent 15 months in Mosul, so I knew the Kurds very well, they talked a good game, it was a pretty army, it didn't fight very well when push came to shove. So we've had to bring them up to a level of competency that you would've have hoped was better beforehand but they are now contributing pretty actively."
Thomas observed how the fight against ISIS has grown tougher in some respects and noted that Iranian forces and Iran backed groups are now a factor, saying "it's also an indescribably complex environment when we are a coffee-breath close to Shia Popular Mobilization Forces riding around us, riding in M1 tanks that we provided the Iraqi army back in the day."
Thomas even revealed that during a trip to Erbil, Iraq, his plane happened to be parked next to the plane of Maj. Gen. Qasem Soleimani, the Iranian commander of the Quds Force.
"We bump into them everywhere," Thomas said of the Iranians.
On the question of the fate of Abu Bakr al-Baghdadi, Thomas said he still is relevant as the "iconic" head of ISIS. But he added that "we haven't heard from him lately, he's been an utterly ineffective leader by our assessment, if at all."
"I monitor the same reports that everybody else does that he's dead, you know that he's not quite dead yet, he might be south of Raqqa. The bottom line is we will get him eventually, it's not safe for him on this earth for what he's done and what his organization has done," Thomas said.
Thomas was one of three senior US figures to state that Baghdadi is still alive on Friday, along with Secretary of State James Mattis and National Counterterrorism Center Director Nick Rasmussen.
Mattis told reporters, "I think Baghdadi is alive. I think that he is alive and I'll believe otherwise when we know we've killed him. But we're going after him but we assume he's alive"
Rasmussen also appeared in Aspen, saying he's "seen nothing that would lead me to believe that the leader of ISIS has been removed from the battlefield."
Thomas went on to say, "We have absolutely dismantled his network, I mean everyone who worked for him initially is dead or gone. Everybody who stepped to the plate the next time is dead or gone. Down through a network where we have killed a conservative estimate of 60,000 to 70,000 of his followers."
Thomas also publicly disclosed that, in the past, US troops have come close to getting Baghdadi.
"In fact sometimes we've been closer than we know, it's just the vagaries of combat I think and counterterrorism targeting," he said. "There were points in time where we're particularly close to him, unfortunately there were some leaks about what we were up to at that time."