The Egyptian President Mohammed Mursi has promised people in Sinai that stability will be restored to the tense border region with Gaza and Israel.
He was paying his second visit to the area since last weekend’s killing of 16 Egyptian border guards.
“We will never allow any force whether from outside or inside Egypt to attack a single Egyptian civilian,” said President Mursi.
Military sources said six terrorist suspects had been arrested during what they described as successful raids in north Sinai.
Local people strongly denied those being held were terrorists, doubting the army’s claims.
Leaders of Bedouin tribes – often hostile to the Cairo authorities – have reportedly agreed to help the government try to restore order.
The border was reopened on Friday after being closed following the attack, but only for Palestinians returning to Gaza.
Troops have been massing in the area to contain Islamist militants who are suspected of carrying out the attack.
Israel has agreed to the Egyptian troop reinforcements close to its border.