The U.S. is headed toward deeper military involvement in Iraq, Syria and Libya to fight the Islamic State in Iraq and Syria (ISIS), according to President Obama's former national security adviser Tom Donilon.
"My own judgment is ... we're going to become more deeply involved in both Iraq and Syria going forward here to address the challenge," Donilon said at a Politico event Monday evening.
Donilon, who served as national security adviser between 2010 and 2013, said U.S. forces are "going to have to become deeply involved" in helping Iraqi security forces retake Mosul, the second largest city in Iraq.
He also said he thinks U.S. forces will become "fairly deeply involved" in retaking Raqqa, ISIS's declared capital in Syria.
The U.S. will also have to look at direct military action in Libya, as well, to address a growing ISIS presence there, he added.
"I think we're going to have to look very carefully at directly addressing ISIS's rise in Libya," he added.
"The major approach would be to intensify our building up Iraqi security forces and other forces we're building in Syria, but also taking direct action. We are pretty skilled in this area," he added.
"Taking direct action against ISIS, operations in Iraq and Syria, but also in Libya," he said.
Donilon, who served during the drawdown of U.S. forces from Iraq, said experts were wrong about ISIS posing only a regional threat versus an external threat to the West.
"Experts said that this was an anti-Shia organization principally ... focused on setting up a caliphate in the theater between Syria and Iraq, and that they wouldn't be focused like al Qaeda was on external operations against the West and the United States. That turns out to be wrong," he said.
After ISIS had established itself in Syria and moved into Fallujah, Obama in January 2014 had called ISIS the "jayvee team" who were "engaged in various local power struggles and disputes" when comparing them to al Qaeda.
“I think there is a distinction between the capacity and reach of a bin Laden and a network that is actively planning major terrorist plots against the homeland versus jihadists who are engaged in various local power struggles and disputes, often sectarian," Obama told the New Yorker.
Donilon said that while ISIS is losing ground in Iraq, it's making progress outside Iraq.
"We have a very serious threat that's evolved and metastasized ... we're making progress inside the theater, I think, but they continue to evolve and metastasize and increase the threat outside," he said.
Donilon also said he believes the threat from ISIS to the U.S. is "going up."
"It's much higher in Europe, but it's an evolved threat that we must address in the United States, and I do think that we will see more threats like we had in San Bernardino," he said.