Security sources in northern Sinai said the Egyptian army was attacked Tuesday at dawn with rocket-propelled grenades and machine guns. No injuries were recorded. The sources said that the gunmen were traveling in a pickup truck without license plates when they attacked an army security barrier. An exchange of fire occurred as the militants used vehicle mounted RPGs and heavy machine guns installed on the truck. Like many checkpoint attacks in the region, the attackers broke off and managed to escape. Police forces arrested 97 suspects in relation to a campaign by the Criminal Investigation Department in northern Sinai. Sources said 32 of those arrested in the campaign have been sentenced to imprisonment. The 65 other suspects are under examination.