CAIRO: Islamic State's Egypt affiliate said in a statement on a social media site it carried out an attack in North Sinai on military checkpoints that killed five members of the country's security forces on Saturday.

The deaths occurred when several mortar rounds hit two checkpoints, security sources said earlier.

North Sinai is the epicentre of an insurgency waged by militants who support Islamic State, the ultra-hardline Sunni group which controls large parts of Iraq and Syria and has a presence in Egypt's neighbour Libya.

Egypt's state news agency MENA said the attack by terrorists -- the term the government uses to describe militants -- involved rockets and shooting and that clashes were continuing.

President Abdel Fattah al-Sisi says militants are an existential threat to Egypt, other Arab states and the West.

While a tough crackdown has neutralised his enemies in the mainstream Muslim Brotherhood, Islamic State's Egypt affiliate, Sinai Province, remains resilient despite steady pressure from military operations.

On Thursday, Sinai Province said it fired a rocket at an Egyptian naval vessel in the Mediterranean Sea near the coast of Israel and the Gaza Strip.

The group has killed hundreds of soldiers and police since the army toppled President Mohamed Mursi of the Muslim Brotherhood in 2013 after mass protests against his rule.