Egypt’s chief prosecutor said in a statement on Saturday that the attack on a Sinai mosque a day before has killed 305 people, including 27 children.

In his statement, Nabil Sadeq said that the attack also left 126 people wounded.

Sadeq said the attack was carried out by 25-30 militants who arrived at the mosque in the small town of Bir al-Abd in five all-terrain vehicles. The militants stationed themselves at the mosque’s main door and 12 windows before opening fire on worshippers inside. They also torched seven cars belonging to the worshippers that were parked outside.

There was no claim of responsibility for the attack, the deadliest by Islamic extremists in Egypt’s modern history. The mosque is frequented by Sufi Muslims, a mystic school of Islam that militants consider heretic.

Egyptian President Abdel-Fattah el-Sissi has ordered the construction of a mausoleum in memory of the people killed inside the mosque in northern Sinai.

A presidential statement did not say where the mausoleum would stand or who would be commissioned to build it, but the decision to have one reflects the depth of grief felt by the government over the death of so many people in Friday’s attack.