At least 12 members of Egypt's security forces were killed and eight others injured on Friday when suspected Islamist assailants opened fire at a checkpoint in North Sinai province, an official said.The attack happened in central Sinai area, 40 km from Bir al-Abd town. The official said the assailants used rifles and automatic weapons before fleeing the scene, Xinhua news agency reported.Hundreds of Islamic State-affiliate terrorists have been killed in intensified Egyptian military raids besides arrests of hundreds others in North Sinai as part of the country's "anti-terrorism war" declared following the army-led ouster of Islamist leader Mohamed Morsi in 2013.