US Central Command's Gen. Lloyd Austin told Congress Tuesday that more than 8,500 ISIS fighters had been killed in the U.S. campaign in Iraq and Syria.
As a result of US and coalition airstrikes, and recent gains by Iraqi and Kurdish forces, ISIS "has assumed a defensive crouch" in Iraq.
The Islamic State in Iraq and Syria (ISIS) was also on the defensive in Syria, Austin said in testimony to the House Armed Services Committee.
"We're about where we said we would be" after seven months of airstrikes that began last August, Austin said.
The campaign "has killed more than 8,500 ISIL fighters," Austin said, using another acronym for the terror group, and also disrupted ISIS' ability to maneuver and exercise command and control.
ISIS militants still maintain a limited offensive capability and poses a terror threat to the region, "but make no mistake, ISIL is losing this fight. He (the enemy) will be defeated. He will be defeated," said Austin, the top commander in the region as head of the U.S. Central Command.
Despite the progress against ISIS, Austin said that the Middle East region remained "more chaotic than I have seen it at any point."
Austin's testimony on the death toll raised the question of whether ISIS' ranks were being filled by the influx of foreign fighters faster than CentCom, the Iraqi Security Forces and the Kurdish peshmerga could defeat them.
In testimony to Congress last week, Director of National Intelligence James Clapper said that ISIS now has about 20,000 foreign fighters, up from 16,000 last fall, out of a total fighting force of as many as 31,000.
The HASC hearing was called to hear testimony from Austin and Christine Wormuth, the Pentagon's Undersecretary for Policy, on President Obama's request for a new Authorization for The Use of Military Force, and on the overall strategy in the Mideast.
The testimony was recessed immediately after Austin's opening statement to allow the HASC members to attend Israeli Prime Minister Benjamin Netanyahu's speech to a joint session of Congress in which he argued against the Obama administration's pursuit of a treaty to rein in Iran's nuclear capabilities.
In his opening statement, HASC Chairman Rep. Mac Thornberry, R-Tex., warned against an Iran deal that would permit Iran to have "a threshold nuclear capability. We cannot allow that to happen."
Rep. Adam Smith, D-Wash., the ranking HASC Democrat, said the lack of a deal would increase the threat of Iran acquiring nuclear weapons. "If we don't reach a deal, then the risk of that happening goes up exponentially," Smith said.
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