Washington: The disturbing video released by jihadist militants showing American journalist James Foley being brutally executed is authentic, the White House said on Wednesday.
The video released by Islamic State of Iraq and the Levant (ISIL) also showed another US journalist Steven Sotloff, and appeared on the social media yesterday.
It has now been taken off most of these websites.
"The US Intelligence Community has analysed the recently released video showing US citizens James Foley and Steven Sotloff. We have reached the judgment that this video is authentic," said Caitlin Hayden, Spokesperson National Security Council, the White House.
"We will continue to provide updates as they are available," she said.
She said the US is appalled by the brutal murder. "We express our deepest condolences to his family and friends."
US President Barack Obama was briefed by Deputy National Security Adviser Ben Rhodes on the video by the ISIL.
"The President will continue to receive regular updates," said Principal Deputy Press Secretary Eric Schultz.
Meanwhile, the FBI told Foley`s parents that it believes the video of his execution is genuine, news gatherer GlobalPost reported.
Foley disappeared in Syria nearly two years ago. He worked as a freelance contributor for GlobalPost.
Republican Senator Marco Rubio said the brutal execution of Foley is the latest example of the evil and barbarism of these terrorists.
"ISIL is not a problem for only Iraqis or Syrians to solve. A piecemeal approach will not eliminate the growing threat to the US and our allies," Rubio said.
"If we do not do more to assist our Iraqi partners and those moderate Syrians who are fighting ISIL and directly target ISIL`s leadership and networks in Iraq and Syria, I fear that James Foley will not be the only American to die at their hands," he said.
"Just as al Qaeda`s initial killings of Americans abroad foretold the carnage they would unleash within our borders, this barbaric beheading of a defenseless hostage is the clearest indication to date that ISIL has declared war on the US, on the American people, and on freedom loving people everywhere," Rubio said.