A third explosion near the Ittihadiya Presidential Palace has killed a second policeman, a short while after two previous bombs detonated on Monday, the first killing a police officer and injuring three others.
Lieutenant Colonel Mohamed Lotfi was killed by the last explosion while Colonel Ahmed El-Ashmawy, an explosives expert at the Cairo security directorate, was killed while attempting to defuse the first device.
According to Egypt's Ministry of Health, 13 people were injured in the blasts. Earlier reports had mentioned that three police officers from the explosives department had also been injured.
Two explosive devices were found before the second explosion: one was defused while the other detonated.
Monday marks the first anniversary of mass protests on 30 June 2013 that demanded the ouster of Islamist president Mohamed Morsi.
Since his ouster on 3 July, and the dispersal of protest camps in Rabaa Al-Adawiya and Al-Nahda squares demanding his reinstatement, there have been numerous attacks on security forces, with at least 500 policemen and troops killed, according to the government.
Egypt's Heliopolis prosecution was inspecting the area when the second bomb exploded.
In a statement released on their alleged Twitter account on 27 June 2014, the Agnad Misr Islamist militant group had declared that it managed to breach the presidential palace security.
Furthermore, in a warning to civilians, the statement explicitly identified -- in red bold font -- the exact location of the explosive devices that were found Monday morning.
Agnad Misr, officially designated a terrorist organisation in May 2014 by an Egyptian court, has previously claimed responsibility for a number of operations, including the Cairo University bombing in April 2014.