Egypt has sent more troops to the Sinai town of El Arish as raids against the Islamic militants continue.

The additional numbers follow the disptach of hundreds of troops and dozens of military vehicles to the area on Thursday.

It aims to weed out the militants who have used the security vacuum in the desert region to spread their influence. Gunmen killed 16 Egyptian border guards on Sunday in the bloodiest attack on security forces in Sinai since Egypt signed a peace treaty with Israel in 1979.

Egyptian security officials said the number of militants in northern Sinai is around 15-hundred, but some local tribal leaders say the figure is in the thousands.