President Barack Obama says the U.S. is doing everything in its power to try to rescue an American woman being held by Islamic State militants.

A day after a Japanese journalist held by the militants was purportedly beheaded, Obama says the U.S. and its allies are deploying all available tools to identify a 26-year-old U.S. aid worker's location. He called her captivity heartbreaking.

The president spoke in an interview with NBC Sunday. The interview is airing Monday on The Today Show but the network released excerpts in advance.

The woman was captured last year in Syria while working for aid groups. U.S. officials have asked that the woman not be identified out of fears for her safety.

Obama says he has watched videos of hostages being beheaded. He says "the terrible stuff that's happening" is part of the reason why the U.S. has to be aggressive in going after ISIS terrorists.