President Abdul Fattah al-Sisi said he "will not hesitate to strike terrorist camps anywhere".
The move comes after gunmen in three four-wheel-drive vehicles earlier today attacked a bus carrying worshippers in central Egypt, killing as many as 35 people and wounding a further 24.
Eyewitnesses said masked men stopped the two buses and a truck and opened fire on a road leading to the monastery of Saint Samuel the Confessor in Minya province, which is home to a sizeable Christian minority.
The Health Ministry said that a large number of those killed were children.
Coptic Christians were attacked in their bus en route to a monastery when gunmen opened fire on them
Security forces launched a hunt for the attackers, setting up dozens of checkpoints and patrols on the desert road.
The grand imam of al-Azhar, Egypt's 1,000-year-old centre of Islamic learning, said the attack was intended to destabilise the country.
"I call on Egyptians to unite in the face of this brutal terrorism," Ahmed al-Tayeb said from Germany, where he was on a visit.
Horrifying acts of terrorism in pictures
Wed, April 12, 2017
Some of the most horrifying terrorist attacks of all time from 9/11 to Mumbai, these murderous acts killed several thousands of people and caused millions of pounds of damage to properties worldwide.
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9/11, September 11th bombings in 2001 is one of the worst and most murderous attack to date. Two hijacked planes were crashed into the Twin Towers of The World Trade Center in New York City, killing 2,800 people
Mr al-Sisi met earlier with security officials in the wake of the attack.
In a televised speech, President al-Sisi said: "We will not hesitate to protect our people from the evil."
Egypt carried out six air strikes on Derna in Libya, military sources are indicating.
Relatives of killed Coptic Christians grieve during their funeral at Abu Garnous Cathedral
The sources said the strikes took place at around sundown.
Mr al-Sisi said: "The terrorist incident that took place today will not pass unnoticed. We are currently targeting the camps where the terrorists are trained."
He said Egypt would not hesitate to carry out further strikes against camps where people were trained to carry out operations against Egypt, whether those camps were inside or outside the country.
The military said the air strikes were ongoing.
More to follow…