Cairo, Egypt (CNN) - At least 28 people were killed in Egypt after unidentified gunmen opened fire on a bus carrying Coptic Christians in what officials are calling a terror attack.
Ten assailants wearing fatigues and face masks fired on the passengers from three four-wheel drive vehicles on a desolate stretch of desert road, Egypts Interior Ministry told CNN.
Hours later, Egypt responded with airstrikes against terrorist camps, President Abdel Fattah al-Sisi said in an on-camera statement, according to state-run Nile TV.
The Christians were traveling Friday to a monastery, St. Samuel the Confessor, around 100 km (62 miles) northwest of the city of Minya when they came under fire, the ministry said.
Twenty-three others were injured, some of whom are now in critical condition, Minya Gov. Essam El-Bedewy told Egyptian satellite channel ONTV.
Men, women and children are among the dead and injured, officials said.
The exact location of Fridays airstrikes was unclear but Nile TV reported that Egypt has targeted terrorists in the Sinai Peninsula and on the border with Libya.
In a statement Friday, President Donald Trump said the "merciless slaughter of Christians in Egypt tears at our hearts and grieves our souls."
"Wherever innocent blood is spilled, a wound is inflicted upon humanity," the statement said. "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 attack comes as the country is still under a three-month state of emergency period following twin attacks on Coptic churches on Palm Sunday last month that killed dozens of people. ISIS claimed responsibility for those attacks.
Bodies lie in the desert after the bus attack on Coptic Christians near Minya in Egypt on Thursday.