EL-ARISH, Egypt — Militants attacked a crowded mosque during Friday prayers in the Sinai Peninsula, setting off explosives, spraying worshippers with ******* and ******* at least 200 people in the deadliest ever ****** on Egyptian civilians by Islamic extremists.

The ****** targeted a mosque frequented by Sufis, members of *****’s mystical movement, in the north Sinai town of Bir al-Abd. Islamic militants, including the local affiliate of the Islamic State group, consider Sufis heretics because of their less literal interpretations of the faith.

The IS affiliate has been waging a stepped-up campaign of ******** in northern Sinai for years and has claimed ****** ******** on churches in the capital, Cairo, and other cities, ******* dozens of Christians. It also is believed to have been behind the 2016 ******* of a Russian passenger *** that ****** 226.

But this was the first major militant ****** on a ****** mosque and the startling ********* eclipsed any past ******* of its kind, even dating back to a previous Islamic militant insurgency in the 1990s.

The militants opened **** from four off-road vehicles on worshippers inside the mosque during the sermon, blocking off escape routes from the area by blowing up cars and leaving the burning ****** blocking the roads, three ****** officers on the scene said.

******* including some 130 ******* were rushed to local hospitals, they added, speaking on condition of anonymity because they weren’t authorized to brief reporters.

No one claimed responsibility immediately following the ******, but IS has targeted Sufis several times in the area in the past, notably beheading a leading Sufi religious figure, the blind sheikh Suleiman Abu Heraz, last year and posting photos of the ******* online.

Images circulating on social media showed dozens of bloodied bodies wrapped up in sheets laid across the mosque floor, while others revealed dozens of relatives queuing up outside the hospital as ambulances raced back and forth.

Resident Ashraf el-Hefny said many of the ******* were workers at a nearby salt firm who had come for Friday services at the mosque, which had contained some 300 worshipers.

“Local people brought the ******* to hospital on their own cars and trucks,” he said by telephone.

Egypt’s state news agency reported the ******** toll, citing “official sources,” revising it upward several times following the officials’ initial reports.

MENA reported that Egypt’s presidency declared a three-day ******** period, as President Abdel-Fattah el-Sissi convened a high-level meeting of security officials.

Egyptian president Abdel-Fattah el-Sisi has condemned the extremist ****** on a mosque in the troubled Sinai Peninsula, calling it “criminal” and “cowardly” and expressing condolences to the ******* and their families.

In a statement after the meeting, el-Sissi said the ****** “will not go unpunished” and that Egypt will persevere with its *** on *********. The suffering of the ******* was not in vain, he added, and will only “add to our insistence” to combat extremists. Addressing the nation later on television, he repeated his view that Egypt was fighting a battle for the rest of the *****.

Cairo’s international airport boosted security following the ******, with more troopers and forces seen patrolling passenger halls, conducting searches and manning checkpoints at airport approaches.

State condolences poured in for Egypt, including messages from ******, the United Arab Emirates, the U.S., ******, France and ******* condemning the ********.

President ************ denounced what he called a “******** and cowardly ********* ****** on innocent and defenceless worshippers in Egypt.”

“The ***** cannot tolerate *********” he said on Twitter, “we must defeat them militarily and discredit the extremist ideology that forms the basis of their existence!”

Security forces have been battling militants in northern Sinai for years, but ******* to date have focused on military and ****** assets, although assassinations of individuals IS considers government spies or religious heretics are not uncommon.

Hundreds of soldiers and militants have been ****** in the conflict, although exact numbers are unclear as journalists and independent investigators are banned from the area.

Egypt is also facing a growing number of ******* by militants in its Western Desert, including an ****** last month that ****** 16 ******, according to an official tally issued by the Interior Ministry. Security officials have told journalists that dozens more, including high-ranking counterterrorism officers, perished in the Oct. 20 ****** some 135 kilometres (84 miles) southwest of the capital, Cairo.