BENGHAZI, Feb. 16 -- Libyan army warplanes on Monday bombed the eastern city of Derna, which is controlled by a Libyan affiliate of the Islamic State (IS) militant group, according to an army commander.

The airstrikes targeted IS bases in the city, and more raids will be carried out later Monday and Tuesday, said Libyan air force commander Saqer al-Joroushi.

There were no immediate reports on casualties of the airstrikes.

The air raid came a day after the IS released a video purportedly showing the beheading of 21 Egyptian Coptic Christians who had been abducted in Libya.

Libya's internationally recognized House of Representatives on Sunday issued a statement condemning the "heinous act," saying Libyans and Egyptians will be united to confront the terrorists.

Egyptian jets on Sunday carried out airstrikes on several sites including some weapons depots in Derna.

Derna fell to militants loyal to the IS last year and has become a major training base for Libya's extremists. Besides the eastern coastal city, Libya's central city of Sirte has been also been seized by IS militants recently.

Libya is now deadlocked in a dogfight between a pro-secular army and Islamist militants, making the country a recruiting ground for extremists.