Islamic State claims to have burned alive a Jordanian pilot in a new video released by the militant group.
Mu'ath Al Kassasbeh was taken captive by IS when his fighter jet crashed in Syria in late December.
Images of his apparent murder have been circulated by IS supporters on Twitter.
They show a man in a cage with a line of fuel leading to him.
The fuel is then lit and the cage bursts into flames.
Sky's Tom Rayner, in Amman, said Mr Al Kassasbeh's family are aware of the reports, but have not been contacted officially by the Jordanian government.
They said they would not believe anything until the video is verified.
Sky's Foreign Editor Sam Kiley said: "I think all of this indicates a level of desperation on behalf of Islamic State."
He added: "This will be a cause of considerable dismay within Jordan."
Middle East analyst Shashank Joshi said the brutality of the killing would only serve to stiffen resolve in Jordan, and see efforts against the IS extremists stepped up.
He told Sky News: "If their intent was to split the coalition by threatening violence it's almost certainly going to fail.
"I would anticipate Jordan will continue to remain in the military coalition."
Jordan had been involved in negotiations to free Mr Al Kassasbeh.
In his home town of Ay, which sits in the Karak Mountains 90 miles south of the capital Amman, there have been demonstrations against the country's involvement in the US-led coalition bombing IS.
Speaking to Sky News on Sunday, Mr Al Kassasbeh's brother Jawdat Al Kassasbeh said such sentiments were widely held.
"The Jordanian people in general and our cousins here in this village are saying this war is not our war. It is not our war," he said.
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