The family of an American aid worker held hostage by Islamic State has received confirmation of her death.

"We are heartbroken to share that we've received confirmation that Kayla Jean Mueller has lost her life," the 26-year-old's parents said in a statement released on Tuesday.

"Kayla was a compassionate and devoted humanitarian. She dedicated the whole of her young life to helping those in need of freedom, justice, and peace."

The White House also issued a statement on Tuesday confirming Ms Mueller's death.

She was taken prisoner in Aleppo, Syria, on 4 August 2013, after leaving a Spanish Doctors Without Borders hospital.

The native of Prescott, Arizona, was thought to be the terrorist group's last remaining American hostage.

According to the Site Intelligence Group, which monitors extremists, IS said Ms Mueller died on Friday after Jordanian warplanes struck the building where she was being held.

The Jordanian government initially dismissed the claims as "criminal propaganda" and US officials said they could not confirm the report.

But over the weekend, Ms Mueller's family received a private message from her IS captors that contained "additional information", said Bernadette Meehan, spokeswoman for the White House National Security Council.

President Obama said: "No matter how long it takes, the United States will find and bring to justice the terrorists who are responsible for Kayla's captivity and death.

"ISIL is a hateful and abhorrent terrorist group whose actions stand in stark contrast to the spirit of people like Kayla.

"On this day, we take comfort in the fact that the future belongs not to those who destroy, but rather to the irrepressible force of human goodness that Kayla Mueller shall forever represent."