A top Pentagon officer warned the Senate Armed Services Committee on Tuesday that the Islamic State operating out of Afghanistan may be able to strike the United States in as little as six months.

According to Colin Kahl, the undersecretary of defense for policy, while ISIS-K, as the organization in Afghanistan is known, and al Qaeda both desire to "perform external operations, including against the United States," neither can do so right now. ISIS-K could "create that capability in anywhere between six and twelve months," according to Kahl, but al Qaeda may take "a year or two" to be ready to carry out strikes outside of Afghanistan.

ISIS-K has carried out many suicide attacks in Afghanistan since the Taliban seized power in August, especially targeting the Shia minority.

"It is our assessment that the Taliban and ISIS-K are mortal enemies," Kahl said. "So the Taliban is highly motivated to go after ISIS-K. Their ability to do so, I think, is to be determined."