LOS ANGELES (KABC) -- President Barack Obama said the entire world is "appalled" by the brutal killing of American journalist James Foley.
Speaking from Martha's Vineyard in Massachusetts on Wednesday, the president offered condolences to Foley's family.
"Jim was a journalist, a son, a brother and a friend. He reported from difficult and dangerous places, bearing witness to the lives of people a world away," the president said. "Jim was taken from us in an act of violence that shocks the conscience of the entire world."
The terrorist group ISIS posted a graphic video online Tuesday that showed the beheading of the journalist. In the video, Foley, 40, is forced to make a statement saying he wishes he wasn't American. Then his executioner addresses Mr. Obama in English, saying the killing is payback for the killings of Muslims in the recent American bombings in Iraq.
Special operations troops were sent to Syria this summer on a secret mission to rescue American hostages, including journalist James Foley, held by Islamic State extremists, but they did not find them, the Obama administration said Wednesday.
Officials said the rescue mission was authorized after intelligence agencies believed they had identified the location inside Syria where the hostages were being held. But the several dozen special operations forces dropped by aircraft into Syria did not find them at that location and engaged in a firefight with Islamic State militants before departing.
Foley's parents also addressed the media Wednesday, saying they are very proud of their son.
"Jim had a big heart. We just pray that Jim's death can bring our country together in a stronger way," said Foley's mother, Diane. "Jim would never want us to hate or be bitter. We are just very proud of Jimmy."
Foley had been captured in 2011 covering the conflict in Libya. At that time, he was detained for six weeks and released. He returned to reporting and then went missing in 2012 in Syria while covering the brutality of the Syrian regime as a reporter for the GlobalPost.
GlobalPost CEO Phil Balboni confirmed to ABC News that his news organization received an email from Foley's captors last week stating their intention to execute the journalist.
Mr. Obama said the U.S. will continue to confront Islamic State extremists. According to the Associated Press, a U.S. official said American fighter jets and drones conducted nearly a dozen airstrikes in Iraq since Tuesday even as the militants threatened to kill a second American captive.
At the end of the video of Foley's killing, a second man -- identified as American journalist Steven Sotloff -- is shown and the militant warns that he could be the next captive killed in retribution for any continued U.S. attacks in Iraq. Sotloff was kidnapped near the Syrian-Turkish border in August 2013 and freelanced for Time, the National Interest and MediaLine.
Mr. Obama says ISIS is guilty of cowardly acts of violence, including killings and abductions of women and children. He says the group targets Christians and other minorities and aims to commit genocide. The president called ISIS a "cancer" that has no place in the 21st century.
"We will continue to confront this hateful terrorism and replace it with a sense of hope and civility. That's what Jim Foley stood for, a man who lived his work, who courageously told the stories of his fellow human beings, who was liked and loved by friends and family," the president said. "Today the American people will all say a prayer for those who loved Jim. All of us feel the ache of his absence, all of us mourn his loss."
The Associated Press contributed to this report.