Beheading video of James Wright Foley shocks as ISIS warns TIME journalist Steven Sotloff is next

Terrorist group ISIS posted a horrific video of American freelance photo-journalist James Wright Foley being beheaded in revenge for US airstrikes to fight off the group in Iraq.

The video was posted Tuesday, which shows the 40-year-old journalist on his knees as a masked terrorist stands by him before the beheading.

Foley, who worked for GlobalPost, was missing since 2012 after he was taken hostage at gunpoint in northern Syria.

WATCH LIVE: President Obama's statement on James Foley murder

The graphic video of the beheading was posted with the title: 'A Message to America'. Moments before his murder, Foley left a message for his brother. "I died that day, John, when your colleagues dropped that bomb on these people. They signed my death certificate."

He continues, "I wish I had more time, I wish I could have the hope of freedom and see my family once again, but that ship has sailed. I guess all in all, I wish I wasn't American."

Foley's brother John is thought to be working in the US Air Force.

At the end of the video, the executioner can be seen walking around another journalist, Steven Joel Sotloff, who went missing in 2013, threatening to kill him as well. "The life of this American citizen, Obama, depends on your next decision," the masked executioner says.

Sotloff has worked for TIME, the National Interest, and Media Line. He went missing in August 4, 2013 near Aleppo, Syria.

After a video of Foley's beheading went viral, the White House released a statement: "We have seen a video that purports to be the murder of US citizen James Foley by ISIL. The intelligence community is working as quickly as possible to determine its authenticity. If genuine, we are appalled by the brutal murder of an innocent American journalist and we express our deepest condolences to his family and friends. We will provide more information when it is available."