CAIRO – Egyptian helicopter gunships and tanks pounded suspected hideouts and weapon caches of Islamic militants, killing nine people Saturday in the northern Sinai Peninsula in what locals say is the largest operation in the lawless region for years.

Officials say that the military is hunting hundreds of militants believed to be responsible for a series of attacks in the region they overran after the fall of autocrat Hosni Mubarak in 2011. The militants, the officials say, belong to a number of well-known al-Qaida-inspired groups that seek the establishment of an Islamic Caliphate in northern Sinai, a region bordering Israel and the Gaza Strip.

Attacks in the region have increased following the July 3 military coup that toppled President Mohammed Morsi, an Islamist, prompting the military offensive.

Early Saturday, residents say they saw winding columns of trucks and armored vehicles pour into the area. Some said they hadn’t seen soldiers on foot in their villages in decades. Communications were jammed for hours, as authorities seized control of two telephone exchanges.

Military helicopters hovered overhead in a dozen villages concentrated near two border towns of Rafah and Sheikh Zuweyid, security officials said. Airstrikes targeted shacks believed to be gathering points of militants, they said. Soldiers later stormed homes searching for suspected fighters.

“Successive strikes are aimed at causing paralysis of the militant groups and cutting communications between each other,” a security official said. “The offensive is carried out within a time frame where there will be periods of calm for intelligence before resuming once again.”

“We aim for cleansing the whole region of militants and prevent them from coming back,” he added.

The officials spoke on condition of anonymity as they were not authorized to publicly brief journalists.

In a statement, Army spokesman Col. Ahmed Mohammed Ali said nine suspected militants were killed on Saturday and nine others detained.

Earlier, another official said “dozens” were wounded in the Sinai offensive. Conflicting casualty figures come from militants taking away the corpses of their comrades and treating their wounded, a security official said. Smoke could be seen rising from villages and troops set up a cordon to prevent militants from escaping as others combed the area, he said.

Troops arrested a number of suspected militants but others managed to escape to mountainous areas in central Sinai, an official said.

In the past, militants used a vast network of underground tunnels linking Egypt with Gaza as a way to escape security crackdowns. However, over the past two months, the military has destroyed more than 80 percent of them.