UNITED NATIONS — As her aides anticipated an important announcement about Israeli-Arab diplomacy yesterday, sources in Jerusalem and Washington said Secretary of State Rice has encountered enough resistance from all sides to lower her expectations for a breakthrough.

Israeli officials have spoken to a top White House official in recent days, using friendly Washington contacts to go “over Condi’s head” to describe several of her new ideas as unrealistic, a Jerusalem source, who declined to be identified, told The New York Sun.

Specifically, according to three officials involved in this week’s flurry of diplomatic activity in Washington, Jerusalem, Arab capitals, and the United Nations, Ms. Rice intended to intensify her shuttle diplomacy between Israeli and Palestinian Arab leaders, in an attempt to get them to start negotiating “final status” issues.

Prime Minister Olmert, who met with Ms. Rice last night, “didn’t like that idea,” an Israeli official said.

Jerusalem opposes conducting negotiations now on such issues as final borders between Israel and a future Palestinian Arab state, control over Jerusalem, and the fate of so-called Arab refugees. Instead, Israel insists on sticking to an incremental sequence described in the so-called road map, which calls for an end to violence first.

The president of the Palestinian Authority, Mahmoud Abbas, recently entered into a unity government with Hamas, defined by America as a terrorist organization, which can veto any agreement reached with Mr. Abbas. The unity government has yet to recognize Israel, respect prior signed agreements, or renounce violence, as Washington and its partners have stipulated.

“Rice wants to show progress, but the regional laws of physics are against her,” an official involved, who asked for anonymity, said.

Mr. Olmert reportedly agreed yesterday to “open ended” meetings with Mr. Abbas, but only to discuss “humanitarian issues,” as he did prior to the formation of a unity government with Hamas.

An Arab League summit that will convene tomorrow in Riyadh, Saudi Arabia, is expected to reaffirm a five-year-old plan known as the “Saudi initiative.” But Arab foreign ministers yesterday failed to make any amendments to the plan, leaving several of its provisions unacceptable to Jerusalem.

Ms. Rice had scheduled a press conference yesterday afternoon, Israel time, where her aides expected an important announcement, but the press conference was rescheduled for this morning after her discussions with Mr. Olmert continued late into last night.

“I don’t intend by any means to take control of the Palestinian-Israeli bilateral dialogue,” Ms. Rice told reporters yesterday, when asked about “final status” issues after meeting Israel’s foreign minister, Tzipi Livni. “What my role is is to assist the parties, and I’ve been doing it this time in parallel, and I think that’s a good way to do it, to explore the issues before them, the possibilities of a political horizon, but also concrete issues of how to deal with their daily lives.”

At today’s press conference Ms. Rice is aiming to announce a future meeting in the region of the group known as “the quartet” — America, the European Union, Russia, and the United Nations. The new twist is that this meeting would include several Arab countries — Saudi Arabia, Egypt, Jordan, and the United Arab Emirates — as well as Israel. But though Mr. Olmert said he “would not hesitate to participate,” details involving the expanded meeting had yet to be finalized late last night.

“It is a very interesting, useful idea to consider,” Secretary-General Ban told reporters. “But we need more consultations.”

On his first tour of the region in his new role, Mr. Ban met with Israeli representatives from across the political spectrum, and the main topic was the Saudi initiative, also known as the Arab plan. The plan demands several territorial and other concessions by Israel in return for eventual diplomatic recognition by Arab states.

“The Arab plan is exactly that — Arab,” the opposition Likud leader, Benjamin Netanyahu, told Mr. Ban, according to Israeli press reports. “It is good for the Arabs, but not for Israel.”

Mr. Netanyahu cited two objections to the plan: its approach to a “right of return” to Israel for 4.5 million descendants of Arabs who fled Palestine in 1948; and its insistence that Israel withdraw to an armistice line that existed in the West Bank between 1948 and 1967.

Israel’s vice premier, Shimon Peres, asked Mr. Ban to convey his thanks to King Abdullah of Saudi Arabia for his involvement, an aide to Mr. Peres, Yoram Dori, told the Sun.