President Abdel-Fattah El-Sisi said Egypt reserves its right to retaliate against the killing of 21 Egyptian Copts by the Islamic State (IS) group in Libya at the suitable time and place.
The president added that the National Defence Council has met on Sunday night to decide the course of action to be taken in response.
IS published a graphic video on the internet Sunday purportedly showing the beheading of Coptic Christians it said it had kidnapped recently, and vowed to fight "crusaders."
In a televised speech on Sunday night, El-Sisi said he ordered the Egyptian government to provide full support to the families of the victims, and tighten a ban Egyptians' travel to its western neighbor.
He also said he issued directives to the government to take necessary steps in order to secure and facilitate the return of Egyptians trying to leave Libya.
El-Sisi added he commissioned Egypt's Foreign Minister Sameh Shoukri to travel to New York in order to hold talks with senior United Nations officials and members of the Security Council.
The minister, El-Sisi said, would "demand the international community live up to its responsibilities by taking necessary actions in line with the UN convention, and to declare that what is happening in Libya threatens international peace and security."