(VOVworld) - The United States on Tuesday confirmed the death of an American female hostage held by the Islamic State (IS).

Kayla Jean Mueller in a photo taken in May, 2013 (Photo: AP)

Kayla Mueller, a 26-year-old humanitarian aid worker, was captured in Syria in August, 2013, in Aleppo, the war-ravaged city in northern Syria. The IS claimed last week that Muller had been killed in an air strike by a Jordanian warplane on Raqa, Syria, the militant group's self-proclaimed "capital". US President Barack Obama pledged to "find and bring to justice the terrorists who are responsible for Kayla's captivity and death."