The Pentagon says Washington sent special operations troops to Syria this summer on a secret mission to rescue American hostages, including journalist James Foley.
But the operation failed.
The revelation came a day after Islamic State militants released a video showing the beheading of Foley. They also threatened to kill a second American hostage if the U.S. continues air strikes in Iraq.
U.S. President Barack Obama says Washington stands firm in its fight against the al-Qaida offshoot.
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Producer : Xinhua News Agency