A petrol bomb attack on a Cairo disco killed at least 16 people and wounded two in the early hours of Friday as a blaze broke out, police said.
Police launched a manhunt after the perpetrators fled the scene of the firebombing in the Agouza neighbourhood of the Egyptian capital.
An initial toll had put the number of deaths at 12.
A thick cloud of smoke was seen billowing from the fire-ravaged nightclub.
According to a security source, the attack appeared to have been the result of a dispute between employees of the nightclub and a group of youths.
While Egypt is regularly hit by extremist violence, particularly targeting security forces, attacks on nightclubs are rare.