A senior Israeli official described Egypt's new government on Friday as a "shocking dictatorial force" and predicted there would be no official, high-level contacts between the two countries, which signed a peace treaty in 1979.
The remarks by Amos Gilad, a top aide to Defence Minister Ehud Barak, were some of the harshest yet about the rise to prominence of the Muslim Brotherhood and President Mohamed Mursi, who was elected in June.
Speaking at a security conference, Gilad said the liberal forces behind the uprising which ousted former president Hosni Mubarak in 2011 had evaporated.
"From this democracy what has sprung is a shocking dictatorial force," he said in comments broadcast on Israel Radio.
"Where are all the young people who were demonstrating in Tahir Square? They have vanished."
Mursi has faced some criticism at home from non-Islamists concerned about other voices being marginalised in Egypt. On the whole, however, Egyptians acknowledge he is a democratically elected leader and any disagreements should be resolved in the political arena or at the ballot box.
Despite the peace treaty, relations between Israel and Egypt have never been warm and Israelis watched with consternation as the once-banned Brotherhood rose to prominence. Mursi resigned from the Brotherhood - which describes Israel as a racist and expansionist state - on taking power and has avoided inflammatory language.
He has said Egypt would continue to abide by international treaties, including the 1979 peace deal. Gilad, however, said he saw little prospect of talks.
"The President of Egypt, Mursi, cannot utter the words 'the State of Israel'," he said. Mursi has tended to avoid direct references to Israel in his speeches or public comments. "There is no dialogue between our high-ranking political echelon and this president, and I don't think that there will be," Gilad said.