President Abdel-Fattah El-Sisi implied on Saturday that unnamed foreign countries are interfering with Egypt's domestic affairs, speaking two days after a series of militant attacks killed at least 30 Egyptians in the Sinai Peninsula on Thursday.

"There are some countries that are led by leaders of this terrorist organisation (the Muslim Brotherhood). Do you think these countries will leave us alone?" asked El-Sisi in a televised speech. 

The president did not specify which countries he was referring to, but relations with Turkey and Qatar have been strained since the ouster of Mohamed Morsi.

El-Sisi cut short his visit to Ethiopia where he was due to attend an African Union summit after a series of deadly attacks in North Sinai on Thursday claimed scores of lives. Sinai-based militant group Ansar Beit Al-Maqdis, which has pledged allegiance to the Islamic State, claimed responsibility for the violence.

In his speech, El-Sisi said that Egypt is "paying the price" for choosing to "end the rule of a terrorist group" at its strongest point.

"On 21 June (2013) one of the main leaders of this organisation warned me that they would be getting people from all over the world to fight you, from countries like Afganistan, Iraq, Syria, Palestine and Libya," said El-Sisi, apparently referencing the Brotherhood.

Former president Mohamed Morsi, who hails from the Muslim Brotherhood, was ousted in July 2013 following mass protests nationwide against his rule. El-Sisi, then head of Egypt's military, announced Morsi's ouster on 3 July, in coalition with a number of political and religious figures.

El-Sisi said that the Brotherhood has been planning, widening their horizons and establishing a stronghold all over the world, and said that combating the group will take a long time.

He highlighted in his speech that he knew that there would be a "wave of terrorism" after Morsi's ouster.

"We will not leave Sinai to anyone. With your will the army will win its confrontation with the terrorists," El-Sisi said, visibly emotional.

"It was your will on the 30 June 2013 (the date of mass anti-Morsi protests), and it was one of the hardest decisions taken by you; and it's your will that will keep Egypt strong and able to defeat these terrorists," he said.

The president decried the bloodshed but emphasised that the army and the police are able to combat terrorism.

A new military body to combat terrorism in Sinai was formed by presidential decree on Saturday. 

The Egyptian government designated the Brotherhood a terrorist group in December 2013 amid a crackdown that put thousands of its members behind bars. The group's leaders and representatives have denied any links with militant attacks in Sinai or elsewhere.

The Brotherhood issued a statement on Friday saying that the Egyptian army should return to its barracks to end “the shedding of Egyptian blood in Sinai.”