James Foley beheaded: ISIS claims to have killed US journalist

US joualist James Foley, believed held captive in Syria, has reportedly been beheaded as a "message” to President Obama.

Unconfirmed video and pictures of photojoualist James Wright Foley"s heartbreaking final moments have been published via Twitter by accounts claiming to be associated with the Islamic State, previously known as the Islamic State in Iraq and Syria (ISIS).

Mr Foley was abducted in Syria, in 2012, while covering the campaign against President Bashar al-Assad. He wrote for a variety of media organisations including the AFP news agency.

The identity of the man in the high-definition footage, titled "A Message to America”, has not yet been officially confirmed. The YouTube file, originally uploaded on Tuesday, has since been deleted.

Friends and family of Mr Foley have released a statement saying they are uncertain of what the video shows. "We know that many of you are looking for confirmation or answers. Please be patient until we all have more information”, their Facebook group "Free James Foley” reads.

EXECUTION"S BRUTAL MESSAGE

The gruesome video shows a man in orange prisoner fatigues being led to a remote desert location where he is forced to kneel before reciting a message urging Americans to rise against his "real killer” — the United States.

"I call on my friends, family, and loved ones to rise up against my real killers, the US govement,” he is heard to say. "For what will happen to me is only a result of their complacency and criminality.

US joualist James Foley: Picture: AFP Source: AFP

The US govement has issued a statement saying the intelligence community is working to verify the identity of the men shown in the footage.

"If genuine, we are appalled by the brutal murder of an innocent American joualist and we express the deepest condolences to his family and friends. We will provide more information when it is available.”

TERROR PROPAGANDA TARGETS FAMILY

In the video, the man, who is reported to be Foley, looks calm as he kneels with his hands tied behind his back. Speaking in a level voice with a a microphone attached to his orange robe, he can sometimes be heard swallowing as he bravely continues his speech.

"I call on my brother John, who is a member of the US air force. Think about what you are doing, think about the lives you destroy, including those of your own family.”

He goes on to attack the integrity of the US govement decision: "Think John, who did they really kill? And did they think about me, you, our family when they made that decision?”

His statement, which is presumed to have been prepared for him by the militants, ends with: "I guess all in all I wish I wasn"t American.”

On the job ... This file picture taken September 29, 2011 shows US freelance reporter James Foley resting in a room at the airport of Sirte, Libya. Source: AFP Source: AFP

It"s not the first time Foley has been held captive. He was taken by govement forces in while covering the 2011 uprising against Libya"s Muammar Gaddafi. He was released after six weeks.

In the video released today, the man belived to be Foley is beheaded with a knife by a black-masked man who speaks with what sounds to be a British accent.

"Any attempt by you, Obama, to deny the Muslims their rights of living in safety under the Islamic caliphate will result in the bloodshed of your people,” the executioner intones.

The Islamic State has issued a waing with the video: There will be more executions if President Obama does not end air strikes in aid of the embattled Kurdish and Iraqi Govement forces.

"We will drown all of you in blood,” the jihadists state.

TWO MORE CAPTIVES THREATENED

The propaganda video also shows what it claims to be another US captive, identified as joualist Steven Joel Sotloff.

The dialogue then states his future depends on President Obama"s "next decision”.

Mr Sotloff is a freelance joualist who was abducted in Syria in August 2013.

Execution threat ... Islamic State has threatened the life of another captured joualist, said to be Steven Joel Sotloff, if the United States does not cease air operations over Iraq. Source: Supplied

A third prisoner has been threatened in a separate statement attributed to the Islamic State and addressed to his family.

Warren Weinstein is named as a prisoner the jihadists wish to exchange for one of their own members held by unnamed Weste-affiliated forces.

The open letter, circulating on Twitter, threatens that if Mr Weinstein"s family do not oppose their govement, their son will suffer.

"Your continued silence on the inaction of your govement will only lead to your prisoner dying a lonely death in prison after this deliberate and prolonged neglect on the part of your govement,” the document reads.

"Therefore, if you want Warren Weinstein to be released; do whatever you can to pressurize your govement”.