Cairo, Feb 16 (IANS): Egypt Monday carried out airstrikes on Islamic State (IS) targets in Libya, a day after the group released a video purporting to show the beheading of 21 Egyptians in the neighbouring country.

State television showed footage of Egyptian fighter jets taking off to conduct the strikes, Xinhua reported.

"The strikes came in accordance with the decisions of the National Defence Council, and Egypt's right to defend the security and stability of its great people, and in retaliation of the criminal acts committed by terrorist attacks inside and outside the country," an official statement said.

Speaking on national television hours after the release of the video late Sunday, Egyptian President Abdel Fattah al-Sisi said Egypt would choose the "necessary means and timing to avenge the killings".

The Egyptian Air Force conducted the strikes precisely and came back to its base, the military statement said.

Sisi also declared a seven-day period of mourning over the death of the victims.