Supporters of Egypt's President Abdel Fattah al-Sisi cheer at soldiers during a demonstration against the Muslim Brotherhood and other Islamist groups at Tahrir Square in Cairo November 28, 2014. (Photo:Reuters)
A sound bomb went off on Friday in Abdel-Moneim Riyad Square in downtown Cairo, a short distance from Tahrir Square, witnesses told Ahram Online's reporter at the scene.
No deaths or injuries were reported.
Explosives experts combed the area to guarantee it is clear of further bombs.
There was a heavy security presence in nearby Tahrir Square – the epicentre of the 2011 uprising and the site of recurrent anti-regime protests.
A witness at the scene, Ahmed Abdel-Sattar, a mechanic, said he heard a very loud explosion and then saw police apprehend a young man who was walking close to the source of the sound.
The ultraconservative Salafist Front called for mass protests on Friday to impose Islamic rule and preserve Egypt's "Islamic identity."
Two army personnel died in drive-by shootings earlier on Friday while at least one man died from gunshot wounds amid protests in east of Cairo's Matariya district.
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