JERUSALEM — The election of an Islamist as president of Egypt has heightened concerns in Israel about the future of relations between the two countries — ties that have been increasingly tested since the overthrow of former Egyptian president Hosni Mubarak.

But the worries raised by the victory of Muslim Brotherhood candidate Mohamed Morsi were masked Sunday in a carefully worded official response expressing readiness for continued contacts with the new Egyptian leadership and stressing the importance of the 1979 Israel-Egypt peace accord.

“Israel appreciates the democratic process in Egypt and respects the results of the presidential elections,” said the statement from Prime Minister Benjamin Netanyahu’s office. “Israel looks forward to continuing cooperation with the Egyptian government on the basis of the peace treaty between the two countries, which is a joint interest of both peoples and contributes to regional stability.”

With so much still unknown about what powers Egypt’s new president will have and the future role of the military in ruling the country, Israeli officials and analysts were wary of drawing swift conclusions from Morsi’s victory.

“Ideologically, the Muslim Brotherhood has been against the state of Israel, and its Palestinian branch, Hamas, has waged war against Israel,” said Dore Gold, president of the Jerusalem Center for Public Affairs and a longtime adviser to Netanyahu. “At the same time, in a position of leadership the Muslim Brotherhood will have to feed the Egyptian people and deal with the outside world. So the main question is, how can you encourage the new Egyptian regime to adhere to its international commitments, including the peace treaty with Israel, and follow a pragmatic course. . . . It depends on how the international community responds.”

Zvi Mazel, a former Israeli ambassador to Egypt, said he expected that there would be a “gradual freezing of the peace treaty,” which has been criticized by Morsi as a one-sided pact that Israel has failed to honor, particularly its provisions regarding the Palestinian issue.

The treaty has been denounced in post-revolutionary Egypt as a legacy of the Mubarak era, and Israel has become the occasional target of street protests. A mob stormed the Israeli Embassy last year, forcing the withdrawal of the Israeli ambassador after a border incident in which Israeli troops killed five Egyptian officers. The Israeli forces were pursuing gunmen who had infiltrated from Egypt and carried out an attack that left eight Israelis dead.

The peace treaty, seen as a cornerstone of regional stability and backed by generous U.S. aid to Egypt, is not likely to be revoked, Israeli analysts said, although an Islamist leadership in Egypt could push for revisions.

The Muslim Brotherhood has said that renegotiating the treaty is not a priority.

Binyamin Ben-Eliezer, a Labor Party legislator and former defense minister who had close ties to Mubarak, said he believed that Morsi “will very quickly reach the conclusion that the peace treaty is a strategic interest of Egypt no less than Israel’s.

“People in Egypt are looking for a livelihood, and if he wants to maintain Egypt’s financial resources, he will have to abandon the path of confrontation with Israel,” Ben-Eliezer said, adding that Israel should work to maintain its cooperation with Egypt’s military.

That relationship has been strained by a number of rocket and cross-border attacks on Israel from Egypt’s Sinai Peninsula since Egypt’s revolution, most recently this month, when infiltrators killed an Israeli construction worker building a border fence. After that attack, Israeli Defense Minister Ehud Barak said the new Egyptian president should “take responsibility for Egypt’s international commitments,” improve security in Sinai and end the violence across the frontier.

Morsi’s victory set off celebrations in the Hamas-ruled Gaza Strip, where the Muslim Brotherhood’s ascendancy in Egypt is seen as a key boost, offsetting the economic and diplomatic isolation of the coastal territory by Israel, the United States and European nations.

Mazel, the former ambassador, said that with a government sympathetic to Hamas in Cairo, Israel will find it more difficult to respond to rocket attacks from Gaza with a major military operation, as it had done in the Mubarak years. “The reaction of a president from the Muslim Brotherhood would probably be very harsh,” he said. “Our capability and ability to maneuver will be narrowed.”

Israel will have to adjust to the new regional realities, Ben-Eliezer said. “It’s a different Middle East, more religious, more Islamic,” he said, “and the prime minister will have to find a path to dialogue with the Islamist camp.”