Discarded shoes of victims remain outside Al-Rawda Mosque in Bir al-Abd northern Sinai, Egypt. a day after attackers killed hundreds of worshippers, on Saturday, Nov. 25, 2017. Friday's assault was Egypt's deadliest attack by Islamic extremists in the country's modern history, a grim milestone in a long-running fight against an insurgency led by a local affiliate of the Islamic State group.(AP Photo)
Discarded shoes of victims remain outside Al-Rawda Mosque in Bir al-Abd northern Sinai, Egypt. a day after attackers killed hundreds of worshippers, on Saturday, Nov. 25, 2017. Friday's assault was Egypt's deadliest attack by Islamic extremists in the country's modern history, a grim milestone in a long-running fight against an insurgency led by a local affiliate of the Islamic State group.(AP Photo)

CairoEgypt’s security forces were on high alert on Saturday after striking back at militants whose massacre of more than 300 people at a Sinai mosque raised fears of a new and bloodier phase in the country’s struggle against Islamist insurgents.

Egypt’s state-run Information Service tried to portray Friday’s carnage — at least 305 dead, or about quarter of the male population of the village of Rawda — as a sign of “weakness, despair and collapse” among militants opting for easy civilian targets rather than hitting heavily armed security forces as in the past.

But the level of coordination and precision by the attackers gave no obvious suggestions of a struggling force in an area where Islamic State-inspired groups have gained a key foothold.

The assault on a mosque — a rarity in Egypt — also raised concerns over increasing threats to the country’s minorities, including the Muslim Sufi community hit on Friday.

Survivors and officials described five pickup trucks carrying up to 30 gunmen — some of them masked — converging on the al-Rawda mosque as the imam began his sermon. Some worshippers died in a suicide blast; others were gunned down as they ran. The attackers would later walk among the fallen, 27 of them children, shooting those who appeared to be breathing.

Eyewitnesses said that some had carried a black flag that local residents recognized as belonging to State of Sinai, a local Islamic State affiliate that has remained largely intact even as the Islamic State’s main bases in Iraq and Syria have crumbled.

By the time the attackers left, there were so many bodies on the ground that a fleet of ambulances couldn’t hold them, said a local resident, Muhamed Khalil, 25. Instead, the bodies were piled high on the back of pickup trucks and in the trunks of private cars.

Although no group has claimed responsibility for the attack, suspicion immediately fell on Islamic State-linked militants who have dueled with the army across the desert region.

President Abdel Fatah al-Sissi vowed to avenge the bloodshed with “brute force” — pushed by widespread horror to act with even more resolve. But the contours of a tougher approach remain hazy.

Egyptian security forces have been locked in battle with the country’s Islamic State affiliate for several years. The insurgency has killed hundreds in the heavily patrolled Sinai and militants have struck further afield, including Christian Coptic churches in Cairo and Alexandria.

“The Egyptian government has been describing its reaction to every attack as a harsh response since the summer of 2013, if not before. So it’s difficult to assess what is meant by a promise to do more than that,” said Zack Gold, a nonresident fellow with the Atlantic Council’s Rafik Hariri Center for the Middle East.

Late on Friday, the army said that it launched airstrikes on vehicles apparently used by the assailants, but it was unclear if any suspected militants were killed in the counterattack.

In Rawda, a hamlet off the roadway cutting across northern Sinai, almost no one was left untouched by the violence.

According to Egypt’s 2011 census, Rawda was home to some 2,100 people. Assuming the population had stayed relatively constant, it appeared that Friday’s massacre would have killed around a quarter of the male population.

“We had to bury them in mass graves. In every hole, we would bury 40 or 50,” said the resident Khalil, who help lay entire families together. “People were silent, motionless, unable to grasp the reality of what had happened.”

The massacre also drew acts of kindness. Community members arrived at a hospital in droves to donate blood, first aid kits and all the painkillers they could afford.