CAIRO: Militant group Islamic State has released a video purportedly depicting the mass beheading of 21 Egyptian Coptic Christians in Libya, drawing a strong reaction from President Abdel Fattah al-Sisi who vowed to avenge the killings at a suitable time and place.
The five-minute gruesome video shows handcuffed hostages dressed in orange jumpsuits being murdered by black-clad masked terrorists at a beach near the Libyan capital, Tripoli.
"The sea you've hidden Sheikh Osama bin Laden's body in, we swear to Allah we will mix it with your blood," one of the militants says towards the end of the clip.
The beheadings, the first of its kind outside the territory the radical group controls in Syria and Iraq, drew immediate condemnation in Egypt.
Speaking on national television hours after the release of the video, Egyptian President Sisi said his country" reserves the right to respond in the way and timing it sees fit for retribution from these killers."
He warned that Egypt would choose the "necessary means and timing to avenge the criminal killings".
"Egypt is able to defeat terrorism; because it does that not only to defend itself, but also to defend the humanity," the president said.
Terming the beheading of the Christians as 'vicious', Sisi said a new series of terrorism is spreading across the world and demanded that all people come together to fight it.
During his speech, Sisi offered his condolences to the families of the dead even as he ordered the government to ban Egyptians from travelling to Libya and facilitate the return of others from there.
Sisi called an urgent meeting of Egypt's top national security body to decide the course of action. He also asked the Foreign Minister to travel to New York and participate in the "fighting terrorism" summit.
Earlier in the day, Egypt announced a seven-day mourning period over the beheading.
Egypt's state news agency MENA quoted the spokesman for the Coptic Church as confirming that 21 Egyptian Christians believed to be held by ISIS were dead.
Sunni Islam's top body, Al-Azhar has condemned the "barbaric" beheading.
"Al-Azhar received the news of the execution of a group of innocent Egyptians with great sorrow and grief," Al-Azhar said in a statement yesterday.
Egypt's Copts are the largest Christian community in the Middle East and are estimated to account for around 10 per cent of the Egyptian population.
Thousands of Egyptians have headed to Libya to work since the Egyptian uprising in 2011, despite their government's advice that they should stay away from the country.