The nature and threat of radical Islamic terrorism has been altered and expanded by ISIS, and Al-Qaeda has been quietly rebuilding its capabilities in preparation for ISIS’ defeat on the battlefield, according to terrorism officials.

Three renowned experts on terrorism testified before the House Armed Services Committee on Tuesday, giving detailed briefs on their assessments of the current terrorist threat, and possible actions the U.S. could take as it continues its counterterrorism efforts.

Bruce Hoffman from the Center for Security Studies at Georgetown, Brian Michael Jenkins from the RAND Corporation, and former Green Beret Michael Sheehan from West Point’s Combating Terrorism Center spoke to the challenges military and intelligence services will continue to face, specifically with regard to a resurgent Al-Qaeda and the incredibly complex security situation that will occur once ISIS is driven from its territorial strongholds.