Egyptian military helicopters have conducted several air strikes in the Sinai Peninsula, targeting anti-state fighters, military officials say.

The air strikes took place south of the town of Sheikh Zuwayid and near the border with the Gaza Strip on Saturday, the officials said.

Egyptian state news agency MENA said the army killed nine "protest elements" and arrested nine others during the operation.

Smoke could be seen rising from the towns of Rafah and Sheikh Zuweyid, and troops set up a cordon to prevent fighters from escaping as others combed the area, a security official said.

The northern Sinai, which adjoins Israel and the Palestinian Gaza Strip, has long been a haven for armed groups.

The army has faced an armed anti-state campaign in the area since it ousted President Mohamed Morsi on July 3.

Several dozen soldiers and policeman have died in the violence since then, including 25 conscripts executed on a roadside after their bus came under attack.

'fighters hotbeds'

Sources within the military told Al Jazeera that aircraft fired rockets at "fighters hotbeds", and then soldiers on the ground went in to crack down on suspected fighters.

A witness said the column of tanks, trucks carrying infantry, rocket launchers and other military vehicles on the road on Saturday appeared to be one of the largest units deployed to the area in recent years.

The troop movement follows a failed car bomb attack on Thursday on the Interior Minister's convoy in Cairo that killed one person.

Meanwhile, also on Saturday, Egyptian military engineers defused mortar rounds rigged to explode on a railroad linking the canal cities of Ismailiya and Suez, security officials said.

Police called in the military experts after residents of a village near the railroad spotted the bomb, officials said.

PHOTO CAPTION

Map locates Rafah, Egypt, where 25 off-duty policemen are killed by militants.

Aljazeera