At least 16 people were killed and two wounded in a petrol bomb attack on a Cairo disco in the early hours of Friday, police said.
An initial toll had put the number of deaths at 12.
A thick cloud of smoke was seen billowing from the fire-ravaged nightclub.
State-run media outlet MENA quoted an unnamed security official as saying three men on a motorcycle threw Molotov cocktails into the club in the Agouza district early Friday and then fled.
Police said they did not immediately know the motive behind the firebombing in the central Cairo district.
An official who spoke to Reuters said that one of the perpetrators was a former employee of the establishment, who had been fired.
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.
MENA said the fire was quickly extinguished and security authorities were investigating the attack.