CAIRO (CBSNewYork/CBS News/AP) — Egyptian fighter jets are bombing terrorist bases in eastern Libya following an attack on Coptic Christians that left 28 dead.

Masked men wielding assault rifles opened fire on a bus filled with Coptic Christians south of Cairo Friday morning.

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The bus was traveling to St. Samuel Monastery when the gunmen drove up in three SUVs, surrounded the bus and opened fire, eyewitnesses told Egyptian media.

Some of the gunmen were wearing military uniforms, according to eyewitnesses reports.

A few of the gunmen then boarded the bus and continued to shoot passengers, which included women and children.

At least 28 were killed and 22 were wounded, according to officials. The gunmen then disappeared into the desert, CBS2’s Dana Tyler reported.

There was no immediate claim of responsibility.

“This merciless slaughter of Christians in Egypt tears at our hearts and grieves our souls,” President Donald Trump said in a statement. “But this attack also steels our resolve to bring nations together for the righteous purpose of crushing the evil organizations of terror, and exposing their depraved, twisted and thuggish ideology.

“The bloodletting of Christians must end, and all who aid their killers must be punished,” Trump added.

The Coptic Orthodox Archdiocese of North America said in a statement: “I ask that we remember all the victims and their families in our prayers for console. Our martyrs have received the kingdom of God, and we will continue without ceasing to pray for those who commit these cowardice acts. We pray that these perpetrators may know the true meaning of love.”

Meanwhile in New York City, the NYPD stood guard outside St. Mary and St. Mark Coptic Orthodox Cathedral, providing added peace of mind for church members on Manhattan’s East Side, CBS2’s Jessica Layton reported Friday night.

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Father Gregory Sarougeem prayed for peace after it was shattered in Egypt just hours earlier.

“No one should have to go through such pain,” he said. “We like to take excursions, visit the ancient monasteries. So this was a typical day out for these families.”

Omar Abouzaid served food at his Mediterranean restaurant in the city with a heavier heart than usual.

“Innocent people — could be me, could be my daughter, my wife,” he said.

The Muslim husband and father was thinking of his many Christian friends still living in Egypt, reflecting on the instability of the world right now.

“It happened in Egypt today. We don’t know where the next target is going to be,” he said.

The attack has drawn widespread condemnation, with the United Nations, Pope Francis, Hamas and Hezbollah all issuing statements.

Just last month, Pope Francis traveled to Egypt to show his support for Christians there, who have been targeted by Islamic militants in various attacks.

Mourners cried out over the coffins of the men, women and children killed while chanting, “we will defend out Christianity,” Layton reported.

Coptic Christians make up about 10 percent of Egypt’s population.

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(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)