Egypt's president has vowed to defend the Sinai peninsula in the 'face of terror' after an armed group linked to the Islamic State of Iraq and the Levant (ISIL) claimed responsibility for killing dozens of soldiers and civilians.

President Abdel Fattah al-Sisi made the declaration of Saturday two days after a string of attacks left 45 people dead.

"We will never leave Sinai," Sisi said. "Sinai is ours. Sinai will not seperate from Egypt unless all of us are killed."

In a veiled reference to the Muslim Brotherhood, Sisi blamed the now outlawed group for the fighting.

"I’ve said it before and I will say it again, we are fighting the strongest secret organisation of the last two centuries," he added.

The 'Sinai Province,' previously known as Ansar Beit al-Maqdis, claimed responsibility for Thursday's attack, saying it was retaliating against a government crackdown on supporters of former President Mohamed Morsi.

A military base, a police headquarters, a residential complex for army and police officers and an army checkpoint were targeted in El-Arish, the provincial capital of Sinai.

Shortly after Sisi's speech on Saturday, security forces foiled an attempted carbomb attack on the al-Jourah checkpoint in North Sinai.

Armed groups have regularly attacked security forces in the Sinai since Morsi was toppled by Sisi in July 2013.

Source: Al Jazeera