A military operation is underway in response to the deadly terrorist attack that targeted worshippers at a North Sinai mosque on Friday afternoon, Al-Ahram’s Arabic website reported a military source as saying.

The unnamed source did not reveal the details of the operation, but told Al-Ahram: "the response will be on the ground and will not stop until the elimination of everyone involved in the attack. We are taking our revenge now."

President Abdel-Fattah El-Sisi promised vengeance in a speech to the nation after the attack on Al-Rawdah mosque in Bir Al-Abed after Friday prayers.

Eyewitness told Ahram Online that improvised explosive devices were detonated, after which gunmen opened fire on worshippers at the mosque, which is affiliated with Sufi groups.