Egyptian officials said at least 16 people were killed early Friday in a Molotov cocktail attack on a nightclub in Cairo.
A motive has not been determined for the firebombing, which occurred at El Sayad restaurant and bar in the Agouza neighborhood.
Security officials denied the attack was terrorist-related but provided several apparently conflicting statements.
The Interior Ministry said the incident began with a disagreement between nightclub staff and others, who then bombed the entrance.
Earlier, the MENA state news agency quoted an official who said three men on a motorcycle threw the firebomb into the club and fled the scene.
An official told the Reuters news agency that the attacker was an employee who was recently fired.
Manhunt for suspects
Officials said they have launched a manhunt for the attackers.
Islamic extremists have carried out a wave of attacks since Egypt's Islamist President Mohamed Morsi was overthrown in 2013 and arrested by the military.
Many of the attacks have been claimed by a militant group that has claimed allegiance with the Islamic State militant organization. Most of those attacks have targeted official facilities.
The attacks, most of which have occurred in the insurgent-riddled Sinai Peninsula, have devastated Egypt's crucial tourist industry.