(AP Photo/Raqqa Media Center of the Islamic State group, File)
(AP Photo/Raqqa Media Center of the Islamic State group, File)

The number of fighters joining ISIS has swelled over the summer, according to the CIA.

FOX News Radio's Jared Halpern reports from the White House:

As many as 31,500 fighters could make up the ranks of ISIS... a CIA assessment tripling an earlier estimate.

The new total, the agency says, reflects stronger recruitment since June when the terror group made sweeping gains across Syria and Iraq and established what it sees as a Caliphate.

The strength of ISIS and a growing threat was a the crux of President Obama's speech this week outlining his plan to defeat the group, a strategy that now includes targeting individual ISIS leaders, including it's chief Abu al-Baghdadi.

At the White House, Jared Halpern, FOX News Radio.