File Photo: This undated handout photo obtained February 6, 2015, courtesy of the Mueller family and the office of US Senator John McCain shows 26-year-old Kayla Mueller. (Agence France-Presse)
Somber US lawmakers stood with heads bowed Wednesday during a moment of silence for American aid worker Kayla Mueller, who was held hostage by Islamic State extremists and died.
The House of Representatives' nine-member delegation from Arizona, Mueller's home state, led colleagues in the 12-second silent tribute to a 26-year-old woman that Republican Paul Gosar described as "one of our own."
Mueller, who was seized in the Syrian city of Aleppo in August 2013, "stood as a beacon of light and hope" during a period of intense turmoil and unrest in the Middle East and elsewhere, the congressman said.
"Let us look back fondly upon her life."
President Barack Obama and Mueller's family on Tuesday confirmed her death, with Obama pledging that Washington would hunt down the jihadists it held responsible.
Earlier, IS jihadists claimed Mueller was killed in a February 6 coalition air strike that buried her in rubble.
US officials pushed back on the claim and have said the circumstances of Mueller's death remain unclear.
In the opening paragraph of Obama's letter to Congress seeking war authority against the Islamic State, Obama said IS was "responsible" for the death of Mueller and three other Americans who had been held captive by the group.