Maged Abdelaziz, Egypt's ambassador to the United Nations, said 19 people had been killed Monday in the attack by Israeli troops on a humanitarian aid flotilla off the coast of Gaza, dpa reported.
The earlier death toll was reported at nine, with 30 injuries and the possiblity the death toll could reach 16.
Addressing reporters in New York in the name of the Non-Aligned Movement, Abdelaziz further spoke of an "unjustified" attack and a "flagrant violation of international law."
Abdelaziz demanded that Israel release immediately the flotilla's passengers that it has detained, and that they be returned to their countries of origin.
Like UN Secretary General Ban Ki-moon earlier Monday, Abdelaziz asked for an investigation of events which is "independent" and "fair."