Using the Arabic acronym Daesh for the group in Iraq and Syria, Egypt said that a tough intervention was needed against jihadists in neighboring Libya.

"Egypt renews its call for the international coalition against the Daesh terrorist organization ... to take the necessary measures to confront the terrorist Daesh organization and other similar terrorist organizations on Libyan territories," the Foreign Ministry said in a statement.

An Egyptian armed forces spokesman on Monday announced that the military had carried out an airstrike against militants linked to "Islamic State" (IS). It is the first time Cairo has publicly acknowledged that it is involved in military action in neighboring Libya.

The statement said that Egyptian planes bombed weapons and training camps across the border, before returning home. "The strike has achieved its aims precisely," the army said.

The Reuters news agency reported Libyan air force commander Saqer al-Joroushi as saying up to 50 militants had died in the raids, which had been coordinated between the militaries of both countries.

"There are casualties among the individuals, ammunition and the communication centers belonging to them," al-Joroushi told Egyptian state television on Monday. "The number of deaths are not less than 40 or 50 for sure ... More airstrikes will be carried out today and tomorrow in coordination with Egypt."

Hostages killed on camera

Egypt said its raids were carried out in response to a video purporting to show the mass beheading of Coptic Christians from Egypt. The recording appeared to carry hallmarks similar to those released by the self-proclaimed "Islamic State" in Iraq and Syria.

"Avenging Egyptian blood and retaliating against criminals and killers is a duty we must carry out," the military said. The strikes came hours after Egyptian President Abdel-Fattah el-Sissi threatened a "suitable response" to the killings.

Libyan media said unidentified aircraft had struck sites around the eastern city of Darna. Broadcaster Al-Jazeera reported that two children had been killed when a house on the city's outskirts was hit.

Meanwhile, the Libyan air force hit targets in the cities of Sirte and Benghazi in the east of the country.

Libya's internationally recognized government has been confined to the eastern part of the country since the capital was seized by Islamist-allied militias last year. Meanwhile, Islamist politicians have reinstated a previous government and parliament in the capital, Tripoli, which on Monday condemned the Egyptian strikes as an "attack on Libyan sovereignty."

rc/msh (AFP, AP, dpa, Reuters)