Cairo, Feb 16 (IANS): The Egyptian Orthodox Church confirmed late Sunday that the 21 Egyptian Coptic Christians abducted by the Islamic State (IS) militant group in Libya have been executed by the militants, Xinhua reported, citing Egypt's state-run MENA news agency.

"We watched the painful video. We can confirm (that) the slain were our kidnapped sons in Libya," spokesman for the Coptic Orthodox Church in Egypt, Polis Halim, was quoted by MENA as saying.

The Islamic State (IS) militant group claimed in a video Sunday to have executed 21 Egyptian Coptic Christians abducted in Libya.

The Egyptians were abducted in the Libyan city of Sirte in two separate incidents in December and January, only a week apart from each other.

Halim said that the Church was in contact with a number of government institutions to follow up the situation.

Egyptian President Abdel Fattah al-Sisi has called an urgent meeting of the National Defence Council, following the release of the video.

He also declared a seven-day mourning for the death of the Coptic Christians at the hands of the IS.

Libya has been mired in chaos and civil war since October 2011, when the North Atlantic Treaty Organisation (NATO) began supporting anti-Gaddafi rebels, ultimately resulting in the toppling of the Gaddafi regime.