#IsisMediaBlackout

In a video originally posted on YouTube called "A Message to America," militants claiming to represent the "Islamic State" (IS) appeared to execute a man identified as James Foley, supposedly in retaliation for Washington launching a campaign of airstrikes against the radical group in northern Iraq.

They then threaten to take the life of a man identified in the video as Steven Joe Sotloff, an American who has freelanced for Time Magazine, if US President Barack Obama doesn't end the airstrikes in Iraq. The US Federal Bureau of Investigation (FBI) is investigating the authenticity of the video, which was removed from social media sites on Tuesday.

Shortly after the video went online, a social media campaign called #ISISMediaBlackout was started on Twitter, aiming to stop the footage and other violent videos from being shared. ISIS refers to the radical Sunni group's previous name, the Islamic State of Iraq and Syria.

So far, the Twitter campaign has been shared more than 7,000 times since Tuesday. Twitter user @LibyaLiberty kicked off the campaign.

Meanwhile, CNN Global Affairs Correspondent Elise Labott raised the question of whether it's in the public interest to share the video, in order to highlight the reality of the war in Syria and the dangers that journalists face reporting from there.

But Iraq analyst Sajad Jiyad said it's important for the public not to become desensitized to images of death.

Twitter has taken action, with company CEO Dick Costolo saying that accounts which share the video will not be tolerated.

'Independent and impartial journalist'

Foley went missing in November of 2012 in northern Syria on his way to the Turkish border. He reported for the Boston-based news website GlobalPost as well as the French news agency AFP. The 40-year-old veteran war correspondent had previously reported from Libya and Afghanistan.

"James was working as a brave, independent and impartial journalist covering the dangerous Syrian conflict when he was captured in November 2012," AFP chairman Emmanuel Hoog said.

"His work for AFP and other media organizations was widely admired," Hoog continued. "Nothing could justify his incarceration or any threats against his life. Our thoughts are with his family at this very difficult time."

For more than two years, Syria has been the most dangerous country in the world for the news media, according to the New York-based Committee to Protect Journalists (CPJ). At least 69 journalists have been killed covering the war there and 80 have been abducted. At least 20 journalists, both local and international, are currently missing in Syria. CPJ believes that many of them are held by the IS.

Although Foley's death has not yet been confirmed by US authorities, his mother, Dianne, issued a statement published by GlobalPost.

"We have never been prouder of our son and brother Jim," she said. "He gave his life trying to expose the world to the suffering of the Syrian people."

"We implore the kidnappers to spare the lives of the remaining hostages," she continued. "Like Jim, they are innocents. They have no control over American government policy in Iraq, Syria or anywhere in the world."