An American aid worker who dedicated her life to working with refugees has been killed, allegedly during a Jordanian airstrike, after being held captive by the Islamic State for nearly two years.
The family of 26-year-old Kayla Mueller confirmed her death after receiving a private message from her Islamic State captors which was authenticated by the US government.
A statement posted on an Islamic State website said Ms Mueller was killed on Friday during a Jordanian air strike in the Syrian city of Raqqa.
The US has hit back at claims the aid worker was killed during a coalition airstrike.
“The information that we have is that there is no evidence of civilians in the target area prior to the coalition strike taking place,” White House spokesman Josh Earnest said.
“That certainly would call into question the claims that are made by ISIL,” he said, using an alternate acronym for IS.
Ms Mueller travelled to Turkey in 2012 to work with Syrian refugees, before being captured by ISIL fighters in 2013 as she left a hospital run by the Spanish arm of Doctors Without Borders in the Syrian town of Aleppo.
According to a report by The Guardian, she spent four years prior to her capture working with various aid groups in India, Israel and Pakistan.
The Arkansas woman was a passionate advocate for refugees, telling her local newspaper the Prescott Daily Courier in 2013 that for as long as she lived, she would “not let this suffering be normal”.
In a note written to her family during her 18-month captivity, Ms Mueller said she was being treated with the “utmost respect and kindness” by her captors, and had learned to look for the good in every situation.
“I have been shown in darkness, light and have learned that even in prison, one can be free. I am grateful,” she wrote.
“I have a lot of fight left inside of me. I am not breaking down and I will not give in no matter how long it takes”.
American President Barack Obama praised Ms Mueller following her death, saying she epitomised “all that is good in our world”.
“Kayla represents what is best about America, and expressed her deep pride in the freedoms that we Americans enjoy, and that so many others strive for around the world,” Mr Obama said.
Ms Mueller’s family said they were heartbroken over their daughter’s death but would work every day to honour her legacy.
Journalists James Foley, Steven Sotloff, Kenji Goto, and aid workers Peter Kassig, David Haines, Alan Henning and Haruna Yukawara, Jordanian pilot Moaz al-Kasasbeh are also among those to have been killed while in Islamic State custody.
British journalist John Cantile is still being held by the group, and is being used in Islamic State propaganda videos.