FBI director says bureau is investigating 5,000 terrorism cases across the world

In a startling disclosure, FBI Director Christopher Wray told the Senate Homeland Security Committee on Wednesday that agents are conducting thousands of terror investigations around the world.

"Right now, as I sit here, we're currently investigating about 5,000 terrorism cases across America and around the world and about a thousand of those cases are homegrown violent extremists and they are in all 50 states," Wray said in his prepared testimony.

He said the threat of a large scale, big city attack still exists from groups like Al-Qaeda and ISIS but homegrown violence is as prevalent as ever.

"National security remains the FBI's top priority and counterterrorism is still a paramount concern but that threat has changed significantly since 9/11," Wray said.

Wray said that homegrown terrorists (HVE) "self radicalize" at home and are influenced on social media by the global jihadist movement. They can also attack at a moment's notice.

"This HVE threat has created a whole new set of challenges with a much greater number, much greater volume of threats and each one of them with far fewer dots to connect and much less time to interrupt an attack," Wray continued.

Russell Travers, the acting director of the National Counterterrorism Center, also testified at the hearing, saying the U.S. has "almost 20 ISIS branches of networks ranging from hundreds to thousands of individuals around the globe."

"Our terrorist identities database has expanded by well over an order of magnitude since 2003," he added.