President Obama said the instability triggered by ISIS in Iraq could spread to other countries. (Pool Photo by Dennis Brack via European Pressphoto Agency)

President Obama said that the jihadist group known as the Islamic State of Iraq and Syria "poses a medium- and long-term threat" to the American people, but that other organizations present more imminent danger.

"I think it's fair to say their extreme ideology poses a medium- and long-term threat," Obama said in an interview with CBS News, a portion of which will air Sunday on "Face The Nation." "There are a lot of groups out there that probably have more advanced immediate plans directed against the United States that we have to be on constant guard for."

Obama reiterated that "what we can't do is think that we're just going to play Whac-a-Mole and send U.S. troops occupying various countries wherever these organizations pop up. We're going to have to have a more focused, more targeted strategy, and we're going to have to partner and train local law enforcement and military to do their jobs as well."

Obama's comments came as ISIS seized a key border crossing with Syria in its battle against the Iraqi government. The president said the instability ISIS has triggered in Iraq could spread to neighboring countries.

"Right now the problem with ISIS is the fact that they're destabilizing the country," Obama said. "That could spill over into some of our, you know, allies like Jordan and that they are engaged in wars in Syria where — in that vacuum that's been created — they could amass more arms, more resources."

When pressed on whether such a vacuum in Syria would exist if the United States backed moderate rebel forces there, Obama said yes.

"I think this notion that somehow there was this ready-made, moderate Syrian force that was able to defeat Assad is simply not true," said Obama, later adding: "The notion that they were in a position suddenly to overturn, you know, not only [President Bashar al-Assad] but also ruthless, highly trained jihadists if we just sent a few arms is a fantasy."