The Islamic State (IS) are holding a young American aid worker hostage who was working in Syria, her family says.
IS militants are demanding a ransom of $US6.6 million and the release of US prisoners in exchange for the woman's release, ABC America reports.
It's believed the 26-year-old woman was captured last year while she was working with humanitarian groups in Syria. She's the third American known to have been kidnapped by IS.
Last week, American reporter James Foley was killed by IS militants. Foley had been missing since he was seized by armed men in November 2012.
In a video posted online by IS, a black-clad militant said the 40-year-old freelance journalist was killed to avenge US air strikes against his movement.
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A second US reporter, Steven Stoloff, was paraded before the camera, with the militant saying he would also die unless America changes course.
British officials have said they are close to identifying Foley's killer, who spoke with a British accent.
Britain's ambassador to the United States Peter Westmacott said that "we're not far away" from naming the man in the Islamic State group video.
He said investigators were using techniques including sophisticated voice-recognition software to identify the masked, knife-wielding figure.
