Two Egyptian police officers were killed on Monday while trying to defuse makeshift bombs planted near Cairo's presidential palace by Islamist militants close to the anniversary of the army's overthrow of an elected Islamist president.
Radical Islamists have repeatedly attacked police and soldiers with bombings and shootings since the ousting of President Mohamed Mursi, a member of the Muslim Brotherhood. The Brotherhood denies any link to the violence.
The militant group Ajnad Misr, or Soldiers of Egypt, said it had planted several bombs near the presidential palace to target security forces before realising that civilians could be in danger. It later released a statement saying it had been unable to remove the devices and urging passersby to be cautious.
"There are two explosive devices ... at the corner of the palace at the intersection of al-Ahram and al-Merghani streets", read a statement that appeared on Ajnad Misr's Twitter account.
One police officer was killed as security forces tried to deactivate a bomb found at that location, and a second officer was killed during a similar operation in a nearby street, the interior ministry said in a statement. Monday was the first anniversary of mass street protests against Mursi that led to his removal by the military on July 3. A fierce security crackdown on Islamists ensued and the then-army chief, Abdel Fattah al-Sisi, was elected president in May.
In a televised address to the nation to commemorate the events of a year ago, Sisi used the term "black terrorism" to describe the threats facing Egypt.
"On this day...the first anniversary of the June 30 revolution, black terrorism is still trying to stand in front of the will of Egyptians and their hopes and aspirations," he said in marks that appeared to have been prerecorded at the palace near the site of the explosions.
Egyptian authorities have made no distinction between Islamist militants and the Brotherhood, which has been declared a terrorist organisation by Cairo.
Thousands of Brotherhood leaders including Mursi and supporters have since been arrested, scores sentenced to death and hundreds more have been killed in a campaign to wreck Egypt's oldest Islamist movement.
Eight people were hurt in a series of explosions last week on Cairo's metro, the first attacks in the capital since Sisi was sworn in as president.
The Foreign Ministry said on Monday 255 policemen had been killed in militant attacks since last August.