Foley worked as a freelance contributor to GlobalPost and the Boston-based operation has worked closely with his parents and private security experts in a campaign for his release.
This came as Europe's top powers Wednesday stepped up their response against IS militants who beheaded Foley, as France warned the world faced the "most serious international situation" since 2001.
British Prime Minister David Cameron cut short his holiday and rushed back to London, calling an urgent meeting to discuss how to deal with IS after the man filmed carrying out the execution had a British accent, prompting speculation he is a UK national.
In a highly significant move, Germany said it was ready to send weapons to support Iraqi Kurds in their battle against IS, while France pledged to hold a conference on the security of the region and the battle against the "barbaric" militants.
After other European nations said they would arm Kurdish forces in northern Iraq, "we are ready to do the same," German Foreign Minister Frank-Walter Steinmeier told reporters.
Paris has already said it will dispatch arms to Kurdish fighters but sending weapons is unusual for Germany, which often shies away from foreign military engagements and as a rule does not export arms into live conflict zones, given its past aggression in two world wars.
Germany said it would first send more humanitarian aid and non-lethal equipment such as helmets, night-vision goggles and explosives detectors while it checked what weapons shipments would make sense, in coordination with EU partners.
French President Francois Hollande stressed the gravity of the crisis in Iraq, telling Le Monde daily in an interview: "I think we are in the most serious international situation since 2001" -- the year of the September 11 attacks in the United States.
He said he would "soon propose to our partners a conference on security in Iraq and the fight against Islamic State."
"We need a global strategy against this group which is well-structured, which is well-financed and has very sophisticated weapons, and which is threatening countries like Iraq, Syria and Lebanon," he added.
Global outrage mounted over the IS video posted online late Tuesday showing a masked militant beheading the American journalist, who has been missing since he was seized in Syria in November 2012.
The White House has said that President Barack Obama has been briefed on the contents of the video, as pressure mounted on Washington to consider expanding its military campaign against the militants.
Obama has ordered air strikes on IS forces in a bid to defend the Kurdish regional capital Arbil, military action that has enabled Kurdish and Iraqi forces to push the extremists back and recapture a strategic dam.
The US has carried out further strikes "since yesterday," a senior US defense official told AFP Wednesday.
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