UPDATE | Parents of American woman held by Islamic State notified of her death

WASHINGTON (AP) — Kayla Jean Mueller, a 26-year-old American woman held by Islamic State militants, has been confirmed dead, her parents and the Obama administration said today.

The White House said that Mueller's family received a private message from her captors over the weekend and the information contained in that communication was authenticated by the U.S. intelligence community. It was not immediately clear how and when Mueller died.

"We are heartbroken to share that we've received confirmation that Kayla Jean Mueller, has lost her life," Carl and Marsha Mueller said in a statement. "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."

President Barack Obama said that Mueller, who was an aid worker who assisted humanitarian organizations working with Syrian refugees, "epitomized all that is good in our world."

"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," the president said.