AMMAN - Jordan vowed Thursday to make every effort to save a pilot captured by the Islamic State group in Syria as Washington denied claims the jihadists shot his warplane out of the sky.
Maaz al-Kassasbeh, a 26-year-old first lieutenant in the Jordanian air force, was captured by IS on Wednesday after his F-16 jet crashed while on a mission against the jihadists over northern Syria.
It was the first warplane lost and the first capture of a serviceman since the coalition launched strikes against IS in Syria in September.
It was also a major propaganda victory for the Sunni extremist group, which released several photographs parading the captured pilot.
"The Jordanian government... is making all efforts with several crisis cells to free (the pilot)," government daily Al-Rai said in an editorial Thursday.
"We are confident that our brave one will be released... He has not been forgotten," it said.
Jordan, along with Saudi Arabia, the United Arab Emirates and Bahrain, has joined the US-led coalition carrying out air strikes against IS after it seized control of large parts of Syria and Iraq.
Kassasbeh's plane went down near the Syrian city of Raqa, which IS has used as its de facto capital and where coalition warplanes have carried out regular strikes.
The jihadists and the Britain-based Syrian Observatory for Human Rights claimed the plane was brought down by an anti-aircraft missile, raising concerns for other coalition planes flying in the area.
But the US military dismissed the claim, saying "evidence clearly suggests that ISIL did not down the aircraft", using another name for IS.
"We strongly condemn the actions of ISIL, which has taken captive the downed pilot," US Central Command chief General Lloyd Austin said in a statement.
"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."
IS posted photographs online showing its fighters holding the pilot.
One showed a man being carried from a body of water by four gunmen. Another showed the same man on land, surrounded by almost a dozen militants.
The pilot's father, Youssef, was quoted by Jordanian media as saying the family had been informed by the air force of his capture.
He called on IS to show "mercy" on his son and release him.
UN Secretary General Ban Ki-moon appealed for the pilot's captors to treat him humanely.
"The secretary noted with concern the news of the downing of a Jordanian plane and of its pilot being taken prisoner," a statement from the United Nations said.
"He calls on his captors to treat the pilot in accordance with international humanitarian laws." An activist in Raqa said IS militants were divided over the fate of the pilot, with more extremist foreign fighters wanting him executed and others wanting him kept alive.
There were no further indications Thursday of the pilot's condition.
Despite the loss of the plane, the coalition was reported to have launched further air strikes.
The Observatory, which monitors Syria's conflict with a wide range of local sources, said four strikes had been carried out late on Thursday against IS positions in Kobane, where Syrian Kurdish fighters have been holding off an IS offensive.
Several other coalition strikes took place at Bukamal near the Iraqi border, it said.
Elsewhere in Syria at least 30 IS fighters were killed in clashes with Kurdish militia in the northeastern Hasakeh province, it said.
IS has committed widespread atrocities in areas under its control, including mass executions of captured soldiers and public beheadings of hostages including Western journalists and aid workers.
Syria's conflict began in 2011 as a peaceful revolt against President Bashar al-Assad but evolved into a multi-front civil war that led to the emergence of IS and its expansion into Iraq.