At least 235 people were killed in the North Sinai area of Egypt Friday during a bomb and gun attack on a mosque. Local reports have cited the attack as "one of the deadliest" ever carried out against civilians in North Sinai, CNN reported. The death toll has been revised multiple times since news of the attack first broke.

President Donald Trump called it a "horrible" and "cowardly" terrorist attack.

Horrible and cowardly terrorist attack on innocent and defenseless worshipers in Egypt. The world cannot tolerate terrorism, we must defeat them militarily and discredit the extremist ideology that forms the basis of their existence!

— Donald J. Trump (@realDonaldTrump) November 24, 2017

A group of men opened fire on worshipers at the al-Rawdah mosque in Bir al-Abed Friday following "at least two explosions," according to local media. The blasts caused serious damage to the mosque and left an additional 109 people injured. "They were shooting at people as they left the mosque," a local resident told Reuters. "They were shooting at the ambulances too." Several escape routes have reportedly been blocked by burning cars.

Update: at least 235 killed and 109 injured in Rawda mosque attack in Al-Arish: prosecutor general#BreakingNews #Egypt #Sinai #terrorism pic.twitter.com/5gaa2Xb5NR

— Daily News Egypt (@DailyNewsEgypt) November 24, 2017

At the time of this writing, no group had asserted responsibility for Friday's attack, which occurred in an area that's seen Egyptian security forces fighting an Islamic State insurgency for the past three years in the wake of President Mohamed Morsi being overthrown. Egyptian health ministry spokesperson Khalid Mujahid has described Friday's assault as a "terrorist attack" to local media.

The Egyptian government has declared a three-day mourning period following Friday's attack. President Abdel-Fattah el-Sisi is presently in meetings with security officials. The current status of the attackers is unknown.