The threat of ISIS is "off the charts" and is dragging the U.S. into "uncharted territory," according to a top Obama administration official.

"This is a problem that is off the charts historically," Special Presidential Envoy to the Global Coalition to Counter ISIL Brett McGurk said, pointing out that more than 20,000 foreign fighters have joined the Islamic State in Syria.

"Just put that into perspective: It's about twice the number that went into Afghanistan in the 1980s over a ten-year period to fight the Soviet Union, and those came really from only a handful of countries," McGurk said.

"We're in unchartered territory here."

Lt. Col. Ralph Peters (Ret.) said on "America's Newsroom" that he's glad to see that the Obama administration has finally recognized that ISIS poses a serious threat.

"There is, for me, a deeper problem, in that all administrations, but especially this one, want to address terrorism with lawyers," Peters said. "In wartime, you have to worry about what is effective, what works."

"If you want to make nice, fine. If you want to defeat fanatical ... and apocalyptic terrorists, you clear the battlefield of the lawyers and you do what it takes to win, and that means killing them remorselessly, ruthlessly and relentlessly. Nothing else works."

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