Egypt's foreign minister told his US counterpart, Secretary of State Rex Tillerson, Saturday that the militants who attacked a bus convoy of Coptic Christians a day earlier were trained at camps inside Libya.

Minister Sameh Shoukry said that was the justification for a series of Egyptian airstrikes on the bases.

"There was enough information and evidence of the terrorist elements involved in the (attack) having trained in these camps," a foreign ministry statement said. The facilities were completely destroyed, according to Egyptian officials.

The government didn't say where exactly the sites were located, but Egyptian television reported the airstrikes targeted the eastern Libyan city of Derna.

"The airforce has conducted several intensive day and night-time strikes. They targeted several gatherings of terrorist elements within Libyan territory after coordinating and fully verifying all information," it said.

"The strikes led to the destruction of the planned targets, which included concentrated areas for the training of terrorist elements that participated in the planning and implementation of the Minya attack," it said.

"What you've seen today will not go unpunished. An extremely painful strike has been dealt to the bases. Egypt will never hesitate to strike terror bases anywhere," President Abdel-Fattah el-Sissi said in a televised address to the nation late Friday.

Driving a wedge

He said the attacks on Christians were aimed at driving a wedge between them and the country's Muslim majority.

This is the third major attack against Egypt's small Christian community in the past six months. At least two dozen people were injured in the latest attack, which occurred in the province of Minya.

In April, suicide bombers attacked two churches on Palm Sunday, killing at least 45 people. The attack prompted the government to declare a state of emergency.

In December, an IS suicide bomber attacked another church in Cairo, killing 29 people.

IS jihadists have threatened further attacks. But while police increased security around churches across the country, no one was prepared for a strike on the desert road leading to the Saint Samuel monastery in the southern province of Minya.

The militants appeared to be in no hurry as they perpetrated the massacre, according to a priest and a relative of one survivor.

"They told the men to disembark from the bus, took their identity cards and the gold they had on them, and asked them to the recite the Muslim profession of faith," said Maher Tawfik, whose niece survived.

"They took gold jewellery and money from the women," he said, "as the children hid under the seats."

bik/rc (AFP, Reuters, AP)