Jordan had hoped to free the pilot by exchanging a female prisoner held for an attempted suicide bombing. Early this morning, Jordan executed Sajida al-Rishawi, along with another prisoner. Jordanian government spokesperson Mohammad al-Momani has vowed to wage a firm response to the burning.

Mohammad al-Momani: “Whoever doubted that Jordan’s response would be firm, tough and strong, we will show them the proof, and they will learn that the anger of Jordanians will shake their ranks. The martyred pilot does not belong to a specific tribe, and he is not a son of a specific governorate, but he is the son of all Jordanians, being united as they have been throughout their history.”

Sunni Islam’s most prominent educational center, Al-Azhar, has issued a call for the “killing, crucifixion and chopping of the limbs of Islamic State terrorists.” The burning of the pilot has ignited particular outrage since Islam forbids the cremation of the body. Meanwhile, the United Arab Emirates, a key ally in the U.S.-led fight against ISIS, has suspended its role over concerns about pilots’ safety. Unnamed officials told The New York Times the country stopped airstrikes in December.