The head of public relations for Egypt's caretaker junta called protesters in Cairo "delinquents who need to be thrown into Hitler's ovens."
Gen. Abdel Moneim Kato made the remarks in an interview with the Egyptian newspaper al-Shorouk on Monday.
The invocation of Nazi Germany's most horrific symbol came just hours before Egypt's military rulers foiled a plot to burn down the country's parliament building.
In a separate arson incident at a scientific institute near Tahrir Square rare historical manuscripts, research papers, and maps were destroyed.
Kato’s comment was strongly criticized by several Egyptian activists and politicians.
Mohamed El Baradei, a presidential hopeful, tweeted that the retired general had "a deranged and criminal state of mind!"
The Arabic Network for Human Rights Information in Cairo also denounced the remark, calling Kato an "official who does not hesitate to declare Nazi opinions that incite hatred and justify violence against citizens he disagrees with."
The Egyptian military's crackdown on protesters in the past five days has left at least 14 people dead and hundreds more injured, according to the Health Ministry.
The violence comes amid Egypt's ongoing parliamentary elections, which have seen the Muslim Brotherhood and Salafi al-Nour parties win a combined majority of seats in the first two votes.
The demonstrators are calling on the junta to immediately transfer power to a civilian government nearly one year after the country's revolution toppled former dictator Hosni Mubarak.