The death sentences on the defendants, all tried in absentia, came a day after the military-installed authorities named a new prime minister, who vowed to fight "terrorism" and lure back foreign investors and holidaymakers.

The Suez Canal links the Mediterranean with the Indian Ocean through the Red Sea and is a key trade route between Europe and Asia. It accounts for a huge chunk of Egyptian foreign exchange earnings and government income.

The convictions all relate to offences allegedly committed between 2004 and 2009, before the Arab Spring uprising ended the 30-year rule of Hosni Mubarak in 2011.

They were for "founding and leading a terror group that aimed to attack people's freedom, damage national unity and (attack) the Suez Canal," the source said.

They were also convicted of possessing firearms and explosives, manufacturing rockets and carrying out surveillance of security force buildings in preparation for attacks.

The court referred the death sentences to the mufti, a top Muslim cleric who must approve all executions and has until March 19 to give his decision.

The defendants have the right to appeal.

Since the military ousted Islamist president Mohamed Morsi last July, militants based in the Sinai have stepped up attacks on security personnel.

The army has poured reinforcements into the arid, underdeveloped peninsula, but that has not stopped the gunmen from extending their attacks to other regions, including the heart of the capital.

Nearly 200 kilometres (125 miles) long, the Suez Canal is owned by Egypt but governed by an international treaty that guarantees free navigation.

NJF/NJF