WASHINGTON - US President Barack Obama decried the "cowardice and depravity" of the Islamic State on Tuesday, saying the apparent burning alive of a Jordanian pilot would only strengthen international resolve to destroy the extremists.
Obama said First Lieutenant Maaz al-Kassasbeh's "dedication, courage and service to his country" represented "universal human values that stand in opposition to the cowardice and depravity of ISIL."
"Today, we join the people of Jordan in grieving the loss of one of their own," the president added, as his administration reaffirmed its intention to give Jordan US$3 billion (S$4.04 billion) in security aid over the next three years.
"As we grieve together, we must stand united, respectful of his sacrifice to defeat this scourge," Obama said after the latest in a wave of grizzly filmed murders.
Obama also offered his condolences to King Abdullah II, who is currently in Washington and who met Vice President Joe Biden and Secretary of State John Kerry.
Kassasbeh was captured in December when his F-16 jet crashed over northern Syria, a mission that was part of the US-led coalition campaign against the jihadists.
On Tuesday a slickly produced 22-minute video surfaced online showing a man who appeared to be the pilot engulfed in flames inside a metal cage.
The White House would not speculate on whether the video was released to coincide with King Abdullah's visit to Washington.
Jordanian state television said that Kassasbeh was killed on January 3.
The slaying would redouble international commitment to ensure the Islamic State group "are degraded and ultimately defeated," said Obama.
The extremists seized swathes of territory in Iraq and Syria last year, declaring an Islamic "caliphate" and committing a wave of atrocities.
Countries as diverse as the United States, Saudi Arabia and Jordan responded with "Operation Inherent Resolve," an air-led campaign to pummel the jihadist group.
US Central Command meanwhile admitted that the Islamic State still had the ability "to conduct small-scale operations," despite months of air strikes.
But, it said, "their capacity to do so is degraded and their momentum is stalling."
Attacks have hit the group's "ability to command and control forces; recruit, train and retain fighters, produce revenue from oil sales, and maintain morale."
Islamic State had offered to spare Kassasbeh's life and free a Japanese journalist in return for the release of a female would-be suicide bomber on death row in Jordan.
Jordanian officials announced the female bomber and other jihadists would be executed on Wednesday.