Islamic State terror leaders are reportedly preparing for the fall of its so-called caliphate after the U.S.-led coalition and Russian-backed forces made significant gains in recent months in Iraq and Syria.

The Washington Post reported Tuesday that the terror group’s leaders in Syria are bracing for its strongholds to fall, but vow to continue its wave of terror attacks abroad. U.S. counterterrorism experts believe the recent large-scale attacks in Istanbul and Baghdad are a sign that its reign in the Middle East is dwindling.

Experts still believe that even if the terrorists affiliated with ISIS start to move underground, the group will still remain dangerous abroad.

“Where Al Qaeda was hierarchical and somewhat controlled, these guys are not. They have all the energy and unpredictability of a populist movement,” retired Air Force Gen. Michael Hayden told The Post.