The Egyptian army massed troops and carried out arrests on Friday in an attempt to quell Islamist militants in the Sinai Peninsula close to the borders with Gaza and Israel as President Mohammed Mursi visits the Rafah border crossing for the second time since a week ago when 16 Egyptian soldiers were killed.

According to Maan news agency, five detainees captured Friday morning by the Egyptian army in northern Sinai have been charged of leading “Jihadist” groups and involved in what the Egyptian authorities described as “terrorist attacks” in the Sinai.

Egyptian President Mohamed Morsi has visited the city of el-Arish in North Sinai for the second time since the Sinai attack on Sunday and has vowed to use “a grip of steel to stop the criminals”.

Egypt also temporarily reopened the Rafah crossing into the Gaza Strip, which was shut since the Sinai attack.

 Some 1,500 Palestinians returned to the Gaza Strip on Friday, according to Gaza’s interior ministry.

Maher Abu Sbeiha, director of crossings in the Hamas-run ministry, said that the Rafah crossing would open again Saturday for people traveling into Gaza, but would remain closed to those trying to leave the enclave, Maan new agency reported.

Ismail Haniyeh pledged his support for Egypt’s investigations of the attack, which has led to the biggest Egyptian military assault in the Sinai Peninsula since the October war in 1973.

Hamas has ruled out suggestions that Palestinian gunmen took part in the Sinai killings and has criticized Cairo for imposing “collective punishment” on the impoverished strip by sealing the border.

The Rafah crossing normally sees some 800 people a day leave for Egypt and beyond, according to Reuters. 

Egypt has also moved to seal myriad smuggling tunnels connecting Sinai and the Gaza Strip since Sunday’s attack. the Al-Ahram state-run news website reported on Friday that some 150 tunnels had been destroyed. There are believed to be about 1,000 such tunnels.