In a TV address, President Abdel Fattah al-Sisi condemned ”inhuman criminal killers”
Egypt says it has bombed Islamic State targets in Libya, hours after the group published video showing the apparent beheadings of 21 Egyptian Christians.
State TV said the dawn strikes had targeted camps, training sites and weapons storage areas.
Earlier, President Abdel Fattah al-Sisi said Egypt had the “right to respond” against IS.
A video emerged on Sunday showing a group wearing orange overalls being forced to the ground and decapitated.
IS militants claim to have carried out several attacks in Libya, which is in effect without a government.
“Egypt reserves the right to respond at the proper time and in the appropriate style in retaliation against those inhuman criminal killers,” President Sisi said.
“Egypt and the whole world are in a fierce battle with extremist groups carrying extremist ideology and sharing the same goals.”
The kidnapped Egyptian workers, all Coptic Christians, were seized in December and January from the coastal town of Sirte in eastern Libya, under the control of Islamist groups.