Islamic State supporters claim the militants have shot down a coalition warplane in Syria and taken the Jordanian pilot captive.
The British-based Syrian Observatory for Human Rights monitoring group said the activists say the plane was brought down near Raqqa city, a stronghold of Islamic State fighters in northern Syria.
“We have confirmed reports that IS members took a (non-Syrian) Arab pilot prisoner after shooting his plane down with an anti-aircraft missile near Raqqa city,” the monitors said.
The IS in Raqqa published photographs on jihadist websites purporting to show its fighters holding the captured pilot, with a caption identifying him as Jordanian and giving his name.
Several photographs were released, including one showing the pilot, wearing only a white shirt, being carried from water by four men.
Another showed him on land, surrounded by about a dozen armed men.
The militantsclaimed to have shot down the warplane with a heat-seeking missile.
There was no immediate reaction from authorities in Jordan.
Jordan is among a number of countries that have joined the US-led alliance carrying out airstrikes against IS after the jihadists seized control of large parts of Syria and Iraq.
Saudi Arabia, the United Arab Emirates, Jordan and Bahrain are taking part in the action in Syria alongside the US.