Egyptian jets bombed ISIS targets in Libya on Monday, the day after a video surfaced showing Islamic State members beheading 21 Egyptian Christians, reports Reuters.

Egypt said the early morning airstrike hit militant training sites, camps and arsenals in neighboring Libya.

Libya's air force also participated in the dawn attack on Derna. The coastal city is a base for Islamic State fighters in Libya.

"There are casualties among individuals, ammunition and the (Islamic State) communication centers," Libyan air force commander Saqer al-Joroushi told Egyptian state television.

Al-Joroushi said 40-50 militants were killed, but it is not possible to confirm those numbers.

"More air strikes will be carried out today and tomorrow in coordination with Egypt," Joroushi said.

While it is believed Egypt has supported a Libyan general fighting militants in Tripoli, the mass beheadings have prompted President Abdel Fattah al-Sisi to expand his battle against the Islamic State.

The rogue Tripoli-based parliament, which is supported by some Islamist groups, called Monday's strike an assault on the country's sovereignty.

Cairo has asked the U.S.-led coalition fighting ISIS in Iraq and Syria to include Libya.

Last month, ISIS claimed responsibility for killing nine people during an attack on the Corinthia Hotel in Tripoli, which included an American security contractor.

Egypt, like Jordan, is an Arab nation drawn into the confrontation with Islamic State by the militants' barbaric killings of its citizens.

Jordan has taken a leading role in airstrikes against ISIS in Syria and Iraq this month after the militants released a video in which captured Jordanian pilot Lt. Moaz al-Kasasbeh was burned alive. The Kingdom of Jordan immediately executed two terrorists in its custody, one of which was a female Iraqi terrorist ISIS sought in a prisoner exchange.

The 21 Egyptian Coptic Christians killed by the Islamic State were in Libya searching for work. ISIS soldiers marched the 21 men to a beach, forced them to kneel and beheaded them on video, which was broadcast by an Islamic State website.