Egyptian President Mohamed Morsi has vowed that he will retake control of the Sinai after an attack near the Israeli border left 16 guards dead Al Jazeera reproted
"I have given clear orders to all of our security forces, the armed forces as well as the interior police, to move swiftly in capturing those behind this vicious attack," Morsi said in a television address early on Monday.
"This incident will not go lightly. The security forces will implement entire control over all of these areas within Sinai and will ensure they are controlling it. Those behind the attacks will pay a high price as well as those who have been co-operating with those attackers, be it those inside or anywhere in Egypt."
Sunday's assault at Karem Abu Salem crossing in north Sinai - on the border between Egypt and Israel - took place as gunmen reportedly tried to smash their way across the border into Israel.
The Israeli military said the attack was part of a plot to abduct an Israeli soldier, and two vehicles commandeered by the attackers crashed into Israel, where one blew up.
Egyptian state television said that armed foreign fighters were behind the attack.
"State media is quoting unnamed officials saying that foreign fighters, armed groups, belonging to some previously unknown extremist group have infiltrated the country from Gaza through the tunnels criss-crossing the porous border area," Al Jazeera's Rawya Rageh reported from Cairo on Sunday.
"But we are unable to independently corroborate these allegations just yet," she said.
Rageh said the border police patrol were ambushed by masked armed men while they were having their traditional meal at the end of the daily fast during the Muslim month of Ramadan.
After the attack, Morsi held an urgent meeting with the country's military, and promised a strong response to the attack.
"Those who were martyred in this attack during the time when they were breaking their fast during this holy month of Ramadan, those martyrs, their blood will not go in vain," Morsi said.
A senior security official, speaking on condition of anonymity because he was not allowed to speak to reporters, said seven other guards were wounded in the attack.
He said the attackers seized an armoured vehicle before driving away.
Israel said the attackers commandeered two Egyptian vehicles and tried to storm its border.
One of the vehicles exploded and the second was targeted by Israeli aircraft, Avital Leibovich, a military spokeswoman, said, adding that an unspecified number of the assailants were killed while trying to escape.
Ofir Gendelman, Israeli government spokesman, said seven attackers were killed, four on the Israeli side and three in Egypt.
She said Israeli soldiers were combing the area for other assailants who might still be on the Israeli side of the border. The military instructed Israeli civilians to stay inside their homes.
Ehud Barak, Israel's defence minister, said the attack showed need for "determined Egyptian action" to impose security and "prevent terror in Sinai".
In a statement, Hamas, the Palestinian group controlling the Gaza Strip near Sinai, condemned the attack, calling it an "ugly crime" and extended "deep condolences to the families of the victims and to the leadership and the people of Egypt".
Security officials told Al Jazeera early on Monday that they were in possession of three bodies of the perpetrators of the attack. The three are believed to have been killed while trying to enter Israel.
The official did not specify whether those attackers were killed by Egyptian or Israeli fire. He said that 10 people were believed to have carried out the attack.
Al Jazeera reporters said there was increased security along the border area following the attack. "The entire border area has been sealed with very heavy security on all the roads leading up to Sinai and not just the border area," Rageh said.
Meanwhile Al Jazeera's Cal Perry reported from Jerusalem that Egypt has indefinitely shut down the Rafah crossing on the border with the Gaza Strip.
The Sinai is home to Egypt's Red Sea resorts, a source of lucrative tourist income, and is also where the country's Bedouin, who were long marginalised under the regime of fallen president Hosni Mubarak, are based.
The attack comes a month after armed men believed to be Islamist fighters shot dead two Egyptian soldiers in a dawn raid in north Sinai.
Before the July attack in Sheikh Zuwaid, a town roughly 15km west of the Gaza Strip, the fighters had distributed pamphlets calling on the army, brought in to restore security, to leave the lawless north of the peninsula.
The military sent tanks and soldiers into the region last year to quell Islamist fighters, after receiving permission from Israel. Under a 1979 peace treaty with Israel, Egypt should have a limited military presence in the area.