Egyptian explosives experts defused on Tuesday what seemed to be an improvised bomb in the upscale Zamalek neighbourhood, west of Cairo, Al-Ahram's Arabic news website reported.
Investigations showed the device was composed of a gas-filled cylinder connected to a circuit and cell phone with a timer, state news agency MENA said.
Civil protection forces cordoned off the area after the incident created a state of panic among guests of the nearby Marriott Hotel and local residents of the usually calm district.
Minor bombing attempts have become frequent following the army's ouster of Islamist president Mohamed Morsi in July amid nationwide mass protests against his rule, and a sustained crackdown by the state on his Islamist supporters.
A bomb exploded outside a Cairo court last week, just before Egypt's polling stations were to begin receiving voters' ballots on a new constitution, leaving no casualties.
A spate of recent explosions in densely populated areas has raised fears that militant activity in the border Sinai Peninsula, which has spiked since Morsi's removal, would take its toll on other parts of the country.
In one of the deadliest attacks, a suicide car bombing of a police station north of Cairo killed 16 people last month.