US President Barack Obama will host Jordan's King Abdullah II later Tuesday in a hastily arranged meeting just hours after a video emerged of a caged Jordanian pilot being burned alive by the Islamic State group.
The White House said Obama would welcome the king to the Oval Office at 6:00 pm (2300 GMT) as Islamic State militants drew international condemnation for killing the 26-year-old Maaz al-Kassasbeh.
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.
Obama earlier decried the "cowardice and depravity" of the Islamic State, saying the brutal killing would only strengthen international resolve to destroy the extremists.
The White House would not speculate on whether the video was released to coincide with Abdullah's visit to Washington, where he was not scheduled to meet Obama.
The president said First Lieutenant 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 $3 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.
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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.