He said this was in revenge for the killing of 21 Egyptian Coptic Christians who had been kidnapped in the Libyan city of Sirte.
The spokesman said after the operation in Libya, that the warplanes struck the group’s camps, places of gathering and training, and weapons depots in Libya.
“Let those far and near know that Egyptians have a shield to protect and safeguard the security of the country and a sword that amputates terrorism and extremism,” he said.
It was the first time Egypt has publicly confirmed launching airstrikes against the group in neighboring Libya, where extremist groups, threatening both countries, have grown rapidly following the ouster of Libyan leader Muammar Gaddafi in 2011.
President Abdel al-Sisi has repeatedly said militants based in Libya pose a serious security threat to Egypt.
The 21 Egyptian Christians, who had gone to Libya in search of jobs, were marched to a beach, forced to kneel and then beheaded, the video showed.
Sisi, said hours after the release of the video on late Sunday, that Egypt would choose the “necessary means and timing to avenge the criminal killings.”
After the early morning Libya operation on Monday, Sisi paid a visit to the Coptic Orthodox Cathedral in Cairo to mourn the victims.
Egypt on Sunday declared a seven-day period of mourning for the victims.
Libya’s air force, meanwhile, announced that it had launched strikes in the eastern city of Darna, an extremist base that was taken over by an IS affiliate last year.
Photo Credit: AFP/Getty Images/CNN/Tauseef Mustafa