Egypt Targets Islamic State Militants Who May Have Slipped Into Sinai City

CAIRO—As Egyptian security forces intensify their campaign against Islamic State in the north Sinai region, authorities have isolated the area’s largest city, in a sign of how the insurgency has shifted from the region’s desert expanses to the city streets.

In recent weeks, the state has banned residents from leaving or entering without special permission the regional capital of El Arish, a city of more than 100,000 people, according to a statement from the regional government. The closure has resulted in shortages of food...