The Islamic State in Iraq and Syria (ISIS) has claimed on Tuesday to have executed 40-year-old American journalist James Foley in a revenge attack for US airstrikes in Iraq.

The radical Islamist terror group released a five-minute video showing a masked ISIS militant beheading the reporter, who was kidnapped by the terrorists in Syria in November 2012. The video was posted by the group on YouTube and was titled “A Message to America.”

The execution is carried out by a black-clad masked ISIS militant who speaks English with a British accent. Foley is seen dressed in orange garb, kneeling before the militant. The location of the execution, an open desert, is yet to be determined.

In what is believed to be a scripted message, Foley says, “I call on my friends, family and loved ones to rise up against my real killers – the US government – for what will happen to me is only a result of their complacent criminality.”

His final words to the camera are that when the US began to drop bombs on Iraq, “they signed by death certificate.”

Upon his abduction, Foley’s family began a campaign called “Find James Foley” as part of efforts to secure his release. Following the release of the video, his family said it was time “to seek answers.” On the campaigns Facebook page, Foley’s family requested privacy “as we mourn and cherish Jim.”

“We have never been prouder of our son Jim. He gave his life trying to expose the world to the suffering of the Syrian people,” the message read. “We implore the kidnappers to spare the lives of the remaining hostages. Like Jim, they are innocents. They have no control over American government policy in Iraq, Syria or anywhere else in the world.”

Foley was an experienced Middle Eastern correspondent for several media outlets, including the Global Post and AFP. He had previously covered the war in Libya before heading to Syria at the onset of the civil war.

Witnesses of Foley’s abduction said that the journalist was seized in the northern Syrian province of Idlib on November 22, 2012. No communication was ever established with Foley from the time of his abduction. The recently released video is the first time Foley has been seen since 2012.

The US intelligence community is working to authenticate the video. White House National Security Council spokeswoman Caitlin Hayden said that US President Barack Obama and other members of his administration have reviewed the video.

She said that should the video prove genuine, the US would be “appalled by the brutal murder of an innocent American journalist.”

At the end of the video, a second man, who is being identified as captive American journalist Steven Sotloff, is seen being warned that he could be the next captive killed. Sotloff was kidnapped in August 2013 near the Syrian-Turkish border. He freelanced for Time, the National Interest and MediaLine.

The brutal actions of ISIS are slowly spreading across the Middle East. The Slafi-jihadist terror organization has already taken over parts of Iraq, Syria and Lebanon. In Israel, ISIS militant are believed to have established a presence in the Gaza Strip.

The Israeli intelligence community has been closely following the movement of ISIS over the last several years.