Islamic State says it has beheaded U.S. journalist
The video, titled "A Message To America," was posted on social media sites. It was not immediately possible to verify its authenticity.
Foley, who has reported in the Middle East for five years, was kidnapped on Nov. 22, 2012, by unidentified gunmen.
A Twitter account set up by his family to help find him said early on Wednesday: "We know that many of you are looking for confirmation or answers. Please be patient until we all have more information, and keep the Foleys in your thoughts and prayers."
Islamic State's sweep through northern Iraq, bringing it close to Baghdad and in control of the second city, Mosul, drew U.S. air strikes on the country for the first time since the end of the American occupation in 2011.
The Sunni militant group has declared a caliphate in parts of Iraq and Syria in areas it controls.