RAQQA, Syria, Feb. 6 (UPI) -- The Islamic State says U.S. hostage Kayla Mueller was killed in a Jordanian airstrike in Syria, though neither U.S. nor Jordanian officials are confirming the claims.
The terror group's claims of Mueller's death were posted to social media Friday. The posts included photos of a collapsed building in Raqqa, Syria, along with text saying the 26-year-old was inside the building when it was fired upon.
Unlike previous announcements when captives have been killed, IS did not post photos or videos of Mueller to prove her death.
U.S. State Department spokesman Marie Harf said she couldn't "confirm those reports in any way."
"Obviously, [we are] deeply concerned by these reports," she said. "We have not, at this point, seen anything that corroborates" IS's claims.
Jordanian officials have flat-out denied IS's claims.
"They tried to cause problems internally in Jordan and haven't succeeded," Jordanian Interior Minister Hussein Majali said. "They are now trying to drive a wedge between the coalition with this latest low PR stunt."
The airstrike on Raqqa -- IS's de facto capital -- was part of Jordan's retribution against the terror group for the burning death of Jordanian pilot Lt. Moaz el-Kasasbeh.
Jordanian King Abdullah II vowed retaliation, quoting part of the Clint Eastwood movie, Unforgiven, in the process. The day after a video showing el Kasasbeh's immolation was released, Jordan executed two Iraqi jihadists.
Mueller is a Prescott, Ariz., native and was taken hostage in 2013 in Aleppo, Syria. She was working as a humanitarian in the country.