After a Jordanian military plane crashed over Raqqa province in Syria, ISIS took the pilot hostage, Jordan's state-run news agency Petra said.
Although ISIS claimed it had downed the aircraft, the U.S. military rejected the claim.
"Evidence clearly indicates" that the terrorist group "did not down the aircraft," U.S. Central Command said in a statement.
Cmdr. Gen. Lloyd J. Austin III, overseeing coalition military operations in Iraq and Syria, said, "The Jordanians are highly-respected and valued partners and their pilots and crews have performed exceptionally well over the course of this campaign. We strongly condemn the actions of ISIL which has taken captive the downed pilot.
"We will support efforts to ensure his safe recovery, and will not tolerate ISIL's attempts to misrepresent or exploit this unfortunate aircraft crash for their own purposes."
The U.S. military refers to ISIS by another of its acronyms, ISIL.
Jordanian government spokesman Mohammed al-Momani said his country "initially thought the plane might have been shot at." But later, state news said the plane crashed.
Pilot's family pleads for his life
The family of pilot Moaz al-Kassasbeh is calling on the terrorist group to free him.
Speaking with CNN Arabic, the pilot's brother Jawad al-Kassasbeh asked that ISIS "be supportive of our brother Moaz and to be merciful on him, please send him back to us. He is just a soldier who is following orders and has no authority."
Moaz al-Kassasbeh is a "pious man who prays and fasts and he always flies with his Quran with him," his brother said.
The captured pilot's uncle is retired Jordanian Maj. Gen. Fahd al-Kassasbeh who identified his nephew in photos of the pilot that appeared on ISIS-affiliated Twitter account. The retired general told CNN that he'd asked Maj. Gen. Mansour S. Al Jabour, head of the Royal Jordanian Air Force, to investigate and take all necessary actions.
In one image, four men appear to pushing a dazed and bloody man through shallow water, perhaps to shore.
"The Jordanian pilot Kassasbeh is a model of heroism and all of us stand with his family and his colleagues in-arms," said Jordanian government spokesman Al-Momani told CNN.