CAIRO (Reuters) - Four Egyptian soldiers were killed in an explosion that hit their armored vehicle on Saturday in the northern Sinai peninsula, where the government is battling an Islamic State-led insurgency, security sources said.

The incident occurred about 20 km (12 miles) south of the Mediterranean town of al-Arish.

An insurgency in Egypt’s rugged Sinai region has gained pace since the army toppled President Mohamed Mursi of the Muslim Brotherhood, Egypt’s oldest Islamist movement, following mass protests against his rule in mid-2013.

The revolt, mounted by Islamic State’s Egyptian branch, has killed hundreds of soldiers and police. Militants have also started to attack Western targets within the country.

President Abdel Fattah al-Sisi, the former military chief who led Mursi’s overthrow, describes Islamist militancy as an existential threat to Egypt, an ally of the United States.

On Thursday, 10 soldiers were killed in the Sinai peninsula when their vehicles were hit by two improvised bombs during an operation in which 15 suspected militants were also killed, the army said. Two policemen were killed near al-Arish in a separate incident, the interior ministry said.