After the executions, EU foreign policy chief Federica Mogherini said Brussels was close to its middle-eastern ally in this moment of mourning but condemned the use of capital punishment as a deterrent.
Mogherini's statement read:
A complete opposite stance was taken by the Sunni head of Cairo's al-Azhar Mosque, one of Egypt's most revered religious leaders, who called for the killing, crucifixion or mutilation of those who killed al-Kasasbeh.
Ahmed al-Tayeb, Grand Sheik of the mosque and the head of Sunni Islam's most respected seat of learning, said IS militants deserved the punishment because they were fighting God and his Prophet Mohammed.
Al-Kasasbeh, 26, was captured by Isis in December, as his F-16 crashed near the Islamist stronghold of Raqqa, Syria.
Al-Rishawi, 44, was imprisoned in Jordan after attempting to detonate an explosives belt as part of the devastating 2005 hotel bombings in the capital city of Amman.
Isis had demanded her freedom in exchange for the pilot's life and the release of a Japanese jorunalist who was later eventually beheaded by the group.