The latest attack on Christians in Egypt killed at least 28 people on Friday, some of them children.

The victims were on a bus on their way to the St. Samuel the Confessor monastery, about 140 miles south of Cairo, when a squad of masked gunmen blocked the road with several vehicles, surrounded the bus, and opened fire.

Twenty-five additional victims were reportedly injured in the attack, some of them critically.

Fox News reports:

Video circulating on social media after the attack showed the bodies of about 10 men scattered in the sand on the side of the road with pools of blood around them. Children hysterically screaming could be heard in the background. Local media also reported that the attackers were recording video themselves.

“Arab TV stations also showed images of the badly damaged bus along the roadside, many of its windows shattered and with numerous bullet holes. Footage of the bus’s interior showed blood stains on the seats and shattered glass,” the Fox report continues.

NBC News quotes an Egyptian Health Ministry official who said the victims “included a large number of children.”

Bishop Makarios of the Coptic Orthodox Church in Minya Province told the New York Times that a pickup truck filled with workmen and two buses carrying worshipers were part of the convoy that came under attack.

“The gunmen got on the bus and they shot people point-blank,” he said.

He described the gunmen as emerging from a hideout in a nearby mountain in sport-utility vehicles and attacking at a vulnerable point on a road that had police checkpoints at both ends. “It is a long road, and we can’t expect them to post officers everywhere,” he explained.

“Everyone is trying to identify the dead and wounded. There is no time for anger yet,” the bishop added.

The Times describes Minya province as the part of Egypt where “tensions between Christians and Muslims are highest.” Friday’s slaughter comes after brutal attacks on Coptic churches on Palm Sunday that killed at least 46 people and the December bombing of a Coptic church in Cairo that killed 25.

No group has claimed responsibility for the bus attack at the time of this writing, but authorities suspect the Islamic State (ISIS). The UK Independent notes that ISIS has promised to escalate attacks against Egyptian Christians, warning Muslims to stay away from Christian gatherings that could be targeted.

An ISIS video released in February described Christians as the terrorist group’s “favorite prey” and claimed Allah has given the group orders to “kill every infidel” in Egypt. Propaganda released by the Egyptian branch of ISIS specifically stated that Christian women and children would be killed.

“They have never been targeted in the way that they are now. Egypt is extremely dangerous for Copts in ways it hasn’t been dangerous before,” Council on Foreign Relations Senior Fellow Steven A. Cook told NBC News.

The bus attack drew swift and widespread condemnation.

“Muslim leaders including the Grand Mufti of Egypt and the grand imam of al-Azhar, Egypt’s 1,000-year-old centre of Islamic learning, condemned the act of ‘brutal terrorism’ and called on Egyptians to unite,” the Independent reports.

Israeli Prime Minister Benjamin Netanyahu sent the “condolences of the Israeli people” and said, “Terror will be beaten more quickly if all countries work together.”

The Times of Israel notes that the Palestinian Authority also condemned the attack, as did Hamas, the terrorist group that controls the Gaza Strip. A Hamas spokesman denounced the shooting as “an ugly crime” that benefits only “the enemies of Egypt.”