Egypt has declared three days of national mourning, after at least 305 people were killed in an attack on a crowded Sufi mosque in Egypt’s Sinai Peninsula on Friday. Egyptian officials are calling it the deadliest terror attack in Egypt’s modern history. On Friday, more than two dozen attackers wearing military combat uniforms detonated a bomb inside the mosque, then opened fire with machine guns on fleeing worshipers and set cars ablaze to stop people from being able to escape. Among the victims were at least 27 children. Officials are blaming the attack on a militant group linked to ISIS. This is Mohamed Abdel Fattah, the imam of the al-Rawdah mosque, which was attacked on Friday.

Mohamed Abdel Fattah: “Yesterday’s sermon was on Muhammad, the prophet of humanity, and the week before that was on Muhammad, the prophet for mercy. I believe these are two issues that the entire world, whether Muslims or non-Muslim, need to implement: mercy, forgiveness and humanity. A religion based on humanity will never condone violence or aggression such as this.”

Over the last year, ISIS-linked militants in Egypt have also repeatedly targeted Coptic Christians, bombing two Coptic churches and opening fire on a bus headed to a monastery. Within hours after Friday’s attack, Egyptian President Abdel Fattah el-Sisi appeared on television, vowing revenge for the attack. Only minutes later, Egyptian warplanes carried out multiple airstrikes in the desert of the Sinai Peninsula. The military says they were targeting militants fleeing the attack. We’ll go to Egypt for more on the attack after headlines.