Egypt imposes state of emergency in Sinai after attacks
Egypt has declared a three-month state of emergency in parts of the Sinai Peninsula after at least 31 soldiers were killed in two attacks there.
President Abdul Fattah al-Sisi has declared three days of mourning in the wake of the suspected jihadist attacks.
Egypt's Rafah crossing into the Gaza Strip was also closed, state TV said.
It was the biggest loss of life in decades for Egypt's army, which has been carrying out an offensive against jihadists in northern Sinai.
The area has become increasingly lawless since President Hosni Mubarak was overthrown in 2011. Militants have stepped up attacks since Islamist President Mohammed Morsi was ousted by the army last year.
Egypt in mourning
There has been no claim of responsibility for Friday's suicide blast at an army checkpoint that killed 28 soldiers.
At least 28 others were injured in the attack near El Arish, the main town in the north of the restive peninsula.
Three more soldiers died in a separate shooting at a checkpoint in the town itself.
A state of emergency was declared in the north and centre of the peninsula in the wake of the attack, starting from 03:00 GMT on Saturday, a presidential statement said.
The decision was made after Egyptian President Abdul Fattah al-Sisi called a meeting of the National Defence Council to discuss the security situation.
"The army and the police will take all necessary measures to tackle the dangers of terrorism and its financing, to preserve the security of the region... and protect the lives of citizens," the statement said.
Egypt is in mourning with state television carrying black ribbons on screen, after the latest heavy losses in the lawless Sinai peninsula, says the BBC's Orla Guerin in Cairo.
Communications have been cut, and helicopters and special forces are now searching for militant hideouts, she adds.
Security forces have been carrying out an offensive in northern Sinai, killing and capturing dozens of suspected members of jihadist groups.
In September at least 11 policemen were killed in a bomb attack on a convoy in the peninsula as it travelled through the village of Wefaq, near the Gaza border.
That bombing was claimed by Ansar Beit al-Maqdis, the most active militant group in Egypt. It attempted to kill the interior minister in Cairo in 2013 in a car bomb attack and has issued videos of the beheading of captives.
The group professes backing for Islamic State (IS) group jihadists in Iraq and Syria, although it has not formally pledged its support.