The former Navy admiral credited with coordinating the operation that led to the death of Osama bin Laden says the U.S. and its allies should prioritize fighting Islamic extremists, or else the American people "should not be surprised when the barbarians are at our gate."

The remarks by William McRaven, who is now chancellor of the University of Texas System, were some of his strongest on national security since leaving the military for academia in January. The former commander of U.S. Special Operations Command said sophisticated military equipment, a network of intelligence and continuous action with "boots on the ground" will help defeat the Islamic State group.

"They have invited young men and some women in so that they can act out their greatest perversion. It's not about an ideology. It's not about the caliphate," McRaven said at a national security conference in Austin, the Austin American-Statesman (http://atxne.ws/1SQ6TgZ ) reported.

"I believe that they bring people in because they realize they can kill, they can rape with impunity, they can torture, they can do these barbaric things in the name of Islam."

His stance was not well-received by all in the audience. Before McRaven took the stage, a group of students rose from a table, calling him a mass murderer who perpetuated Islamophobia during his military career.

Another audience member questioned whether McRaven should be publicly supporting war given that he is now the leader of a public university system. McRaven responded that he could exercise his right to free speech even as a chancellor, which garnered loud applause from the audience.

McRaven recently announced plans to establish the UT Network for National Security, an alliance across the system's 14 campuses that would knit together experts in a range of security issues.

"In the end, we know the right strategy: It is continuous and direct action on the extremists until they have no more capacity and no more reach. It will be a generational fight, but if we don't take it on now, then we should not be surprised when the barbarians are at our gate and we're wondering how they got here," McRaven said.