Israeli Prime Minister Benjamin Netanyahu (Photo courtesy Creative Commons).

While the celebration continued in Cairo's Tahrir Square, the Gaza Strip filled with Hamas members and supporters, elated over former Egyptian President Hosni Mubarak's resignation. But Israelis remained largely quiet after Mubarak's announcement, widely interpreted as concern for what comes next in Egypt.

Egypt, which borders Israel to the south, has been one half of a major treaty since 1979 that was considered a major stepping stone in Arab-Israeli relations. But with Mubarak gone, Israeli officials say they don't know what to expect next.

"We don't know who will be running things in the coming months in Egypt, but we have to keep two things in mind," one Israeli official told the New York Times. "The first is that the only example we have of this kind of thing in the region is Iran in 1979. You can't take that out of your mind. The second is that if Egypt pulls back in any way from its peace with Israel, it will discourage anyone else in the region, including the Palestinians, from stepping forward. So the regional implications for us are significant."

The White House insisted Friday after Mubarak stepped down that the new government uphold the 1979 treaty. But Israeli Prime Minister Benjamin Netanyahu expressed early concerns from his country about Egypt's prospective leadership structure earlier this week when he spoke to a pro-Israel group in Europe.

"There are many possible outcomes beyond the liberal, democratic models that we take for granted in out own countries," Netanyahu said.

One of those outcomes involves the Muslim Brotherhood, an Islamist opposing force apparent in several Arab countries, assuming control of the Egyptian regime. One former Israeli official said such a takeover might cause unrest to erupt across the Middle East.

"If there is a free election, I don't see how they can be stopped," Eli Shaked, former Israel ambassador to Egypt told the Christian Science Monitor.

"The Muslim Brotherhood has already said they won't be committeed to the peace treaty. I don't see a military conflict with Israel. But the whole regional order of the last 30 years will be totally shattered."

Israel's calculated silence was unique among reaction from other world leaders, many of which joined President Obama in praising the Egyptian people. Others were more cautious in the response, unable to predict what is next for Egypt.

Amr Moussa, Arab League secretary-general: who announced Friday he would be resigning from his post within weeks: "I look forward to the future to build a national consensus in the coming period. There is a big chance now and a window has opened after this white revolution, and after the president's concession."

Sami Abu Zuhri, Hamas spokesperson in Gaza: "The resignation of Egyptian President Hosni Mubarak is the beginning of the victory of the Egyptian revolution. Such a victory was the result of the sacrifices and the steadfastness of the Egyptian people. We call upon the new Egyptian leadership to take an immediate decision to lift the blockade of Gaza and open Rafah crossing permanently to allow people's free movement and in order for the reconstruction process of Gaza to begin."

Government of the United Arab Emirates: "The UAE, which has closely monitored development in Egypt, confirms its confidence in the ability of the Supreme Council of the Armed Forces in running the country's affairs in these delicate circumstances in such a way that would realize aspirations and hopes of the Egyptian people."

Ban Ki-moon, United Nations secretary-general: Moon called for a "transparent, orderly and peaceful transition" of power. He also called for "free, fair and credible" elections.

Angela Merkel, Chancellor of Germany: "Today is a day of great joy. We are all witness to a historic change. I share the joy of the people of Egypt, with the millions of people on the streets of Egypt.

David Cameron, Prime Minister of the United Kingdom: "Egypt now has a really precious moment of opportunity to have a government that can bring the country together and as a friend of Egypt and the Egyptian people we stand ready to help in any way that we can."

Nicolas Sarkozy, President of France: "France ardently hopes the new Egyptian authorities will take steps that leadto establishment of democratic institutions through free and transparent elections."

Sergei Lavrov, Russian Foreign Minister: "We view the latest news from Egypt as the result of processes carried out by main political forces of the country. This is a sign of the responsible attitude of the authorities to the problem and the wish to achieve national accord. Hopefully, the latest event will promote stability, normal functioning of governmental agencies and the readiness of the opposition to achieve stabilization."

To reach executive producer David McAlpine, click here.

To follow him on Twitter: @DavidMcAlpine

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