Egypt’s public prosecutors linked the massacre to IS militants hours after warplanes launched revenge bombing raids on Daesh hideouts, killing at least 15 fighters, some in vehicles.
Up to 30 masked IS gunmen had travelled in jeeps to the mosque and then stopped anyone leaving by blocking the front door and all 12 windows after Friday prayers.
A bomb was set off and then they mercilessly opened fire with automatic rifles, giving those inside little chance of escaping the carnage.
During the murderous mayhem 27 children were killed and 128 worshippers were injured.
Television pictures showed rows of bloodied bodies inside the blood drenched building.
Wounded survivor Magdy Rezk said from his hospital bed: “When the shooting began everyone was running, and everyone was bumping into one another but I was able to make out masked men wearing military clothing.”
Egyptian defence analysts believe IS fighters fleeing Syria and Iraq have moved to the badlands of North Sinai to join hardliners
No group has claimed responsibility for the outrage at the Al Rawdah mosque in Bir al-Abed, west of El-Arish city but Egyptian forces have been battling an IS affi liate in the region.
Some of the worshippers were Sufis, whom groups such as IS consider targets because they revere saints and shrines, which for Islamists is tantamount to idolatry.
IS has targeted Sufi and Shi’ite Muslims in other countries, like Iraq.
The mosque attack is a shift in tactics for the Sinai militants, who have in the past targeted Christian churches and pilgrims and those supporting the army.
Long suffering Egyptians have struggled through instability since an uprising in 2011 which ousted Hosni Mubarak.
Ex-armed forces commander Abdel Fattah el-Sisi, who became Egypt’s president in 2014 vowing to tackle terrorism, said he would use “utmost force” against those responsible for the country’s worst terrorist atrocity.
“What is happening is an attempt to stop us from our efforts in the fight against terrorism,” he said.
North Sinai, a mostly desert area which stretches from the Suez Canal to the Gaza Strip and Israel, has been a security headache for Egypt.
Attacks in Sinai worsened after 2013 when Sisi led the overthrow of President Mohamed Mursi of the Muslim Brotherhood.
Security at places of worship and key Egyptian buildings was stepped up yesterday as the country began three days of mourning.