On Tuesday morning, a small explosion rocked parts of Heliopolis after an IED planted on al-Hamam street went off, an official at the interior ministry's media center said.
"There were no injuries or damages," the official added.
A bomb squad that examined the area said there were no other bombs in the vicinity.
Meanwhile, police broke up a demonstration on Faisal street by dozens of Muslim Brotherhood supporters.
The protesters raised posters of toppled President Mohamed Morsy and Rabaa signs.
They chanted against the military and the current election process.
Police used tear gas to prevent the demonstrators from getting close to polling stations in the area.
Tuesday marks the second and final day of voting in the 2014 presidential elections.