"What do those who brought downed the (Russian) plane want? They want to ruin tourism as well as our relations with Russia, Italy and with the whole world if he could, to isolate Egypt," Sisi told the attendees.
This is the first time for Egypt to officially indicate that a terror attack is behind the Russian plane crash in the restive peninsula.
Moscow said earlier in mid-November 2015 that a bomb attack brought down the Russian passenger jet in Sinai that killed all 224 people on board in October.
Terrorist activities killed hundreds of policemen and soldiers since the army ousted former Islamist president Mohamed Morsi in July 2013 in response to mass protests against his one-year rule.
The Egyptian president added in his speech that it was the extremists who started the attacks in Sinai, adding that "we could have all coexisted despite different ideologies, but it did not happen."
The crash led some states, including Britain and Russia, to suspend their flights to Egypt's Red Sea resort of Sharm el-Sheikh and to evacuate their nationals over security concerns.