The CIA said Thursday that the number of Islamic State fighters has grown to as many as three times previous estimates, a day after President Obama announced he is drastically expanding the U.S. military campaign against the militants.

A spokesperson for the agency told Fox News that new assessments show that the militant group can muster between 20,000 and 31,500 fighters across Iraq and Syria.

The spokesperson said the new figures were determined after a review of “all-source intelligence reports” on the group from May to August.

The new numbers are a big jump from the agency’s previous estimate that there were at least 10,000 Islamic State fighters.

House Homeland Security Committee chairman Michael McCaul (R-TX) joined Martha MacCallum to respond, and discuss Secretary of State John Kerry's statement that the new U.S. campaign against ISIS should not be called a "war."

She asked McCaul about the "semantics" being used by Kerry.

McCaul answered that the administration has consistently tried to "downplay" the threat posed by ISIS.

"ISIS defies his entire campaign narrative that he's ended the war on terror, that al Qaeda's on the run and this whole thing is over, when in fact the threat level has gone up not down," said McCaul.

Martha pointed back to the U.S. involvement in Libya, when it was called a "kinetic military action."

"Words matter. It's important how you define this to your enemy. And when you pull back and say this is not a war, it's a counter-terror operation, I think it weakens the mission," he said.

McCaul believes the administration is avoiding saying "radical Islam" and mentioning "caliphates" in an effort not to offend the Muslim world.

"It defies reality and it defies what's truly happening across the globe and I think that's a dangerous narrative."

Watch the full interview above.