President Barack Obama and Jordanian King Abdullah II vowed not to let up in the fight against ISIS Tuesday, as Jordanians mourned the death of a military pilot held captive by the militants.

Obama hosted Abdullah at the White House for a hastily arranged meeting Tuesday, hours after a video emerged online purportedly showing 26-year-old Lt. Muath Al-Kaseasbeh burned to death by the militant group. Abdullah, who was on a previously scheduled trip to Washington, arrived after nightfall and made no remarks to reporters as he and Obama sat side by side in the Oval Office.

In the meeting, Obama offered "his deepest condolences" to the king over the pilot's death, the White House said. "The president and King Abdullah reaffirmed that the vile murder of this brave Jordanian will only serve to steel the international community's resolve to destroy ISIL," said White House spokesman Alistair Baskey, using another acronym for the terror group.

Al-Kaseasbeh, who fell into the hands of the militants in December when his Jordanian F-16 crashed in Syria, is the only pilot from the U.S.-led coalition to have been captured to date.

His death sparked outrage in Jordan, where the country's participation in the coalition against the Islamic State group has not been popular. The video emerged following a weeklong drama over a possible prisoner exchange with an Al Qaeda operative imprisoned in Jordan. Before dawn Wednesday, Jordan executed two Al Qaeda prisoners.

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In a statement before his meeting with Abdullah, Obama vowed the pilot's death would "redouble the vigilance and determination on the part of our global coalition to make sure they are degraded and ultimately defeated."

"Lieutenant Al-Kaseasbeh's dedication, courage and service to his country and family represent universal human values that stand in opposition to the cowardice and depravity of ISIL, which has been so broadly rejected around the globe," Obama said.

Vice President Joe Biden, who held a previously scheduled lunch with Abdullah in Washington Tuesday, also condemned the killings and called for the release of all prisoners held by ISIS. The king also held previously scheduled meetings with senators on Capitol Hill.

Abdullah, a close U.S. ally, has portrayed the campaign against the extremists as a battle over values. Sen. Lindsey Graham, R-S.C., emerged from talks with Abdullah predicting that Jordan would have a "strong and forceful" response to the pilot's death.

"The Jordanian response will be more engaged, not less engaged, when it comes to destroying ISIL," Graham said. "The king feels that the gloves are off and that it now is time if you can't negotiate with these people, you're going to have to take it to them, and I think it's going to be more than Jordan."