The Egyptian authorities arrested 15 people on Wednesday for being involved in the violence that swept Sinai since the ouster of Islamist President Mohamed Mursi, security sources said.
Seven of the detained suspects are Palestinians and four are Egyptian nationals who lived in a rented apartment in Arish that supporters of Mursi used to attack security checkpoints, according to the sources.
The sources added that the army arrested four people near a tunnel connecting Egypt to Gaza, as they were suspected for joining a militant group that planned more attacks in Sinai.
The militant attacks in Northern Sinai had left at least 50 people killed and 93 wounded since the crackdown on the Islamist protest camps in Cairo.
Ninety percent of those who died in the attacks were army and police conscripts, whereas most of the injured are civilians who were present near attacked police stations, according to a healthy ministry official in Sinai.
Egypt's military has announced earlier that it was stepping up its presence in Sinai to reduce the ever-increasing Islamist militants' attacks.