JERUSALEM -- Israeli officials are eyeing warily the ascendancy of Mohammed Morsi to Egypt’s presidency, but they say for now that they think Egypt’s military has effectively tied his hands in one of the areas of greatest concern to Israel: cooperation in isolating the Hamas-ruled Gaza Strip.

Longer term, however, they think that Morsi, a member of the Muslim Brotherhood who’s been sharply critical of Egypt’s peace treaty with Israel, is likely to have a negative influence on Israeli-Egyptian relations and on Israel’s relationships with other countries in the region.

“This is a man we don’t feel will be interested in enhancing the ties between Israel and Egypt. This is a man who might want to weaken those ties,” said an official in Israel’s Foreign Ministry who spoke only on the condition of anonymity because Israel’s official line toward Morsi’s election has been positive. “There is a lot of concern that Israel will be dealing with a new reality on the ground.”

Israeli officials fretted particularly about what Morsi’s approach might be to the Gaza Strip, which had celebrated the victory of the Brotherhood, long a close ally of the Islamist group Hamas. Medics in Gaza reported that the celebratory gunfire was so intense that one Palestinian was killed and three others wounded Sunday night after Morsi’s win was announced.

"We will look to Egypt to play a big, leading role, a historic role, regarding the Palestinian cause, in helping the Palestinian nation get freedom, return home and totally end the Gaza siege," Ismail Haniyeh, the head of the Hamas government in Gaza, said in welcoming Morsi’s victory.

But Israeli officials think it’s unlikely that Egypt will move quickly to break Israel’s blockade of Gaza by opening the crossing point to Egypt at Rafah, where Egypt has long restricted the movement of goods and people in cooperation with Israel. They note that Egypt’s Supreme Council of the Armed Forces blocked any change in the Rafah situation last week, when it removed foreign policy from the new president’s authority.

“Israel would be in a very difficult position if Egypt chose to do this, to legitimize Hamas in this way,” the Israeli Foreign Ministry official said.

Legislator Benjamin Ben-Eliezer, Israel’s former defense minister and a close friend of ousted Egyptian President Hosni Mubarak, said it was likely that Egypt’s military would maintain whatever ties with Israel were necessary to continue receiving $2 billion in aid annually from the United States.

Ben-Eliezer said Morsi was likely to chip away at the Egypt-Israel peace treaty through a series of public referendums: “Morsi will want to do as little as possible with Israel while making sure he keeps the American billions.”

He said that one of the tenets of the treaty – a deal that provides Israel with 40 percent of its natural gas – would be the first to be “re-evaluated.”

Over the last year, frequent attacks on the gas pipeline that runs from Egypt’s northern Sinai peninsula into Israel have forced Israel to turn elsewhere for fuel. In April, the Egyptian side of the joint venture that sells natural gas to Israel announced that it was terminating the deal.

“This was the first sign, the first indicator, that the peace deal was unraveling,” said Zvi Mazel, Israel’s former ambassador to Egypt. “It does not bode well.”