A graphic video showing the beheading of photojournalist James Foley was confirmed as authentic by White House officials on Wednesday, causing an international outpouring of prayer.

Foley was covering the Syrian civil war when he was kidnapped nearly two years ago. In the video, he is being held captive by a member of the Islamic State (IS), a terrorist group that controls much of northern Iraq and Syria.

The 40-year-old journalist was also captured in Libya in 2011. In an interview following his release, he explained the significance of his dangerous profession.

"I believe that frontline journalism is important," he told The Boston Globe. "Without these photos and videos and firsthand experience, we really can't tell the world how bad it might be."

He also talked about the power of prayer, saying it gave him an "inner freedom" in spite of his physical captivity.

The world now grieves the loss of the courageous son, brother, and friend.

"Praying for the family and friends of James Foley amid these tragic developments, and for an end to this barbaric violence. ‪#‎StopISIS," Ruth Malhotra ‏of Ravi Zacharias Ministries wrote on Facebook.

"In the wake of the barbaric killing of #JamesFoley - my prayer is that love and peace will triumph, and God will comfort those who mourn," Church of England media officer Tim Mayo posted on Twitter.

"Prayers for the family and friends of #journalist #JamesFoley following horrendous news this morning," priest and Team Rector of East Ham Rob Marshall wrote.

"Brutal murder of #JamesFoley," Coptic Orthodox Church General Bishop Angaelos tweeted. "#Praying repose for his soul, comfort for his family, and safety upon all his colleagues still in the field."

The execution video ends with footage of American journalist Steven Sotloff, who went missing last August from Syria.

"The life of this American citizen, Obama, depends on your next decision," an IS member, cloaked in black, said to the camera, while Sotloff is kneeled in front of him.

President Obama said "the entire world is appalled" by the Muslim extremists' acts in a Wednesday press conference.

"No just God would stand for what they did yesterday or every single day," he proclaimed. "People like this ultimately fail. They fail because the future's won by those who build and not destroy. The world is shaped by people like Jim Foley."