Dozens of supporters of the Muslim Brotherhood were killed in clashes with security forces and political opponents on Sunday, one of the bloodiest days since the military deposed Islamist President Mohamed Mursi in July.
The death toll from the day's violence across the country rose to 53, state media said yesterday, with 271 people wounded.
The Brotherhood denies the military's claims that it incites violence and says it has nothing to do with militant activity, but further confrontations may shake Egypt this week, with Mr Mursi's supporters calling for more protests for today and Friday.
They are likely to be angered by the publication of an interview with Egypt's army chief yesterday in which he said he told Mr Mursi as long ago as February he had failed as president.
Sunday's clashes took place on the anniversary of the 1973 war with Israel - meant to have been a day of national celebration.
Authorities had warned anyone protesting against the army during the anniversary would be regarded as an agent of foreign powers, not an activist - a hardening of language that suggested authorities would take a tougher line.
The Brotherhood accused the army of staging a coup and working with security forces to eliminate the group through violence and arrests, allegations the military denies.
Sinai-based militants have stepped up attacks on the security forces since the army takeover and assaults like that in Cairo's Maadi suburb fuel fears of an Islamist insurgency like one in the 1990s crushed by then-President Hosni Mubarak.
Two people were wounded in the attack on the state-owned satellite receiver station while medical sources said three were killed and 48 injured in a blast near a state security building in South Sinai.
A witness said it was caused by a car bomb.
Security sources said gunmen opened fire on the soldiers in Ismailia while they were sitting in a car at a checkpoint near the city on the Canal, a vital global trade route.
Attacks like the one in Cairo could do further damage to Egypt's vital tourism industry.
David Hartwell, a Middle East analyst at IHS Jane's, said more explosive devices seemed to be being used in the capital.
Army chief General Abdel Fattah al-Sisi, who has promised a political road-map that would lead Egypt to free and fair elections, said in the interview published yesterday that Egypt's interests differed from those of the Brotherhood.
"I told Mursi in February you failed and your project is finished," a newspaper quoted Gen Sisi as saying.
Militant attacks, including a failed assassination attempt on the interior minister in Cairo in September, are deepening the uncertainty in Egypt, along with the power struggle between the Brotherhood and the army-backed government.
Neither side seems willing to pursue reconciliation, raising the possibility of protracted tensions.
Almost daily attacks by al Qaeda-inspired militants in the Sinai have killed more than 100 members of the security forces since early July.