Egypt beefs up troops in Sinai

The Egyptian army has massed troops and made arrests to quell increasingly deadly Islamist militants in the Sinai Peninsula close to the borders with Gaza and Israel.

Egypt also temporarily reopened the Rafah border crossing into the Gaza Strip on Friday, which was closed after militants attacked troops last Sunday and killed 16 soldiers.

State news agency MENA said six "terrorist elements" were arrested during patrols in the North Sinai province and a security source branded them as Islamist hardliners suspected of belong to a jihadist group.

But residents of the small Sinai village of Sheikh Zuayyed said nine people were rounded up, with all insisting the men were good Muslims without links to Islamic extremists.

One woman said her husband, Eid Saeed Salama, 72, was feeding his goats when he was taken away.

And a neighbour said government forces stormed her house and seized her 68-year-old husband Selmi Salama Sweilam who was sleeping, dragging him away "naked".

"Armed men came in. One of them hit me and I fell to the ground," she said, adding that the government forces also made off with 45,000 pounds ($A7000).

A security official said, however, authorities would press on with the operation "until we rid the Sinai of terrorism and criminals," MENA reported.

The agency also reported authorities had released a Canadian student and two Japanese men arrested in the Sinai after determining they entered the country legally.

Trucks carrying dozens of armoured personnel carriers mounted with machine-guns rolled through El-Arish on Thursday and several took up positions in the town.

On Friday, the town of El-Arish near the borders and its environs were reportedly calm but tense, with the military deployed in force.

A tank sat behind a barrier of sandbags painted with Egypt's black, white and red national colours on which was written the slogan "victory or death".

The buildup comes after state television reported that military helicopters and soldiers killed 20 militants on Wednesday in the first such operation in the Sinai in decades, in retaliation for the raid.