ISMAILIA, Egypt (Reuters) - Islamist militants attacked Egypt's security headquarters in northern Sinai on Sunday with a barrage of mortar bombs and machinegun fire and fought police elsewhere in the desert region, wounding three conscripts, security officials said.
The militants had climbed onto the roofs of buildings across from the headquarters building in al-Arish and fired rocket-propelled grenades, one security source said.
Machinegun battles were still being fought in the streets around the building, witnesses said.
About 30 armored personnel carriers backed by helicopters fought militants in the town of Sheikh Zuwaid, 30 km (18.6 miles) east of al-Arish on the Mediterranean coast.
Egyptian forces last month began their biggest security sweep in decades in Sinai after militants killed 16 border guards on August 5 in the most deadly attack since Egypt's 1973 war with Israel.
The government sent hundreds of troops with tanks, armoured vehicles and helicopters to Sinai in a joint operation with police to raid militant hideouts, arrest suspects and seize weapons.
Disorder has spread in Sinai since Hosni Mubarak was ousted in a popular uprising, with Islamist militants stepping up attacks on Egyptian security forces and the Israeli border. Egypt's new president, Mohamed Mursi, has vowed to restore order.
Bedouin tribes in the area have long complained of neglect by central government.
(Reporting by Yusri Mohamed; Writing by Patrick Werr; Editing by Louise Ireland)