Jordan's armed forces said one of its pilots had been captured after a coalition air raid over the province of Raqqa.
An official source said King Abdullah met top commanders in Jordanian military headquarters, where a round-the-clock operations room had been set up after the pilot's capture.
There were contradictory accounts as to whether his aircraft had been shot down or not.
“At this point with the little information we have I think what we can say is that the government will take every necessary step needed in order to secure his (Jordanian pilot held by Islamic State fighters) coming back to his home and his family,” government spokesman Mohammad al-Momani said in an interview broadcast on Jordanian TV.
“We said right from the beginning that this going to be a continuous and long war and we think that we have a duty to defend our country and our region from this wave of terrorism. So Jordan will continue its fight against terrorism and we know that we will win at the end because this is the right thing to do and this is for the sake of our security and stability of this country,” he added.
Islamic State social media published pictures appearing to show the pilot being held by the group's fighters and images of what they said was his Jordanian military ID card.
The images were later verified by relatives contacted by Reuters who said they had been notified by the head of the Jordanian air force that the pilot was First Lieutenant Muath al-Kasaesbeh, aged 27.
The army separately confirmed his name.
“In fact news was received that one of the Royal Air Force airplanes had been downed on Syrian land and there were details also that the pilot Muath al-Kasaesbeh had been captured by Daesh (Islamic State) terrorist group. Our national choice and our nationalist choice to take part in this war and battle against terrorist we had taken into account to ensure the safety of our national soil and our highest national interest to stand against these terrorist groups that target Jordan, its security, and the security of Jordan's leadership,” Momani said.
However, he later told Reuters that new assessments showed there was no indication the plane had been shot at by the militants.
The U.S. military's Central Command also said evidence showed Islamic State did not shoot down the aircraft.
It did not disclose the nature of that evidence.
Jordan is one of the countries participating in the U.S.-led coalition which has been bombing Islamic State targets in Syria since September. REUTERS