The United States plans to issue as early as Tuesday official invitations to a much-anticipated Middle East conference, to be held next week at Annapolis, Md., hoping for strong backing from a select group of Arab nations for the U.S. effort to relaunch Israeli-Palestinian peace talks.

As the U.S. finalizes preparations, the State Department will start sending out invitations overnight for the event, U.S. officials said Monday. The conference will be held in Annapolis on Nov. 27 in between meetings in Washington. The main guests are the Israelis and the Palestinians, and the Bush administration also is inviting Egypt, Jordan, Saudi Arabia, Syria and key international players in the peace process, the officials said.

The invitations are to be sent by diplomatic cable to U.S. embassies in the countries concerned, with instructions to Washington's ambassadors to present them to their host governments' foreign ministries, the officials said. They will ask that each nation send its highest-ranking appropriate official to Annapolis.

The White House has said President Bush will attend at least part of the event chaired by Secretary of State Condoleezza Rice, who also will host a pre-conference dinner at the State Department on Nov. 26, according to the officials, who spoke on condition of anonymity ahead of the announcement.

The State Department held off on invitations in an attempt to get as much done to prepare for the meeting before formally committing to the dates. Details about the meeting, including the guest list and agenda, are expected to be made public in the coming days.

State Department spokesman Sean McCormack said preparations for the meeting were nearly complete and Rice had spent a good deal of time over the weekend calling officials in the Middle East for last-minute consultations.Among others, Rice telephoned Israeli Prime Minister Ehud Olmert, Palestinian President Mahmoud Abbas, Israeli Foreign Minister Tzipi Livni and Egyptian Foreign Minister Ahmed Aboul-Gheit. She also called Lebanese President Fuad Saniora, with whom she discussed both peace efforts and Lebanon's upcoming presidential elections, McCormack said.

U.N. Secretary-General Ban Ki-moon said he spoke with Rice on Sunday and will participate in the Annapolis conference.

"I think this international conference in Annapolis will be a good beginning of a credible process to resolve all these issues," Ban told reporters in New York on Monday. "At the same time, I'd like to see that the participants ... base their expectations on a more practical and realistic assessment."

Bush, who announced plans for the conference in July, and Rice hope Annapolis will launch the first serious round of Israel-Palestinian peace talks in more than seven years with the participants' endorsement of a joint document now being prepared by Israeli and Palestinian officials.

"We do have a sense that they are continuing to make progress, not only on the document but also on what comes after Annapolis," McCormack said.

While awaiting the formal announcement of the conference, the State Department also welcomed pre-Annapolis steps announced Monday by Olmert's cabinet, including the release of Palestinian prisoners and a fresh commitment to not construct new settlements in the West Bank.

"Our view is that the steps that the Israeli government have announced are positive confidence-building measures in the run-up to Annapolis," McCormack said, adding that such steps are points that "both sides can build on, where they can build up that mutual confidence and try to improve daily lives on both sides, for both the Palestinians as well as the Israelis."

Meanwhile, a large group of U.S. lawmakers urged Rice in a letter to make the most of the conference.

"Clearly, robust, hands-on U.S. leadership and diplomacy is necessary to frame not only on what transpires at the meeting, but on what takes place before and after it," said the letter, co-authored by Reps. Gary Ackerman, D-N.Y., and Charles Boustany Jr., R-La., and signed by 133 other members of Congress.

Separately, former national security adviser Brent Scowcroft, a Rice mentor, and other well-known Washington advisers warned Bush and Rice in a letter last month that the session must tackle the "substance of a permanent peace" and that its "failure risks devastating consequences."

The letter is to be re-released Tuesday with more signatures, including Brookings Institution scholar Diana Villiers Negroponte, wife of Deputy Secretary of State John Negroponte.

The Annapolis invitation list has been a poorly kept secret since mid-September, when U.S. officials first began floating ideas about who should attend.

The administration is hoping for significant representation from Arab countries, whose foreign ministers are to meet Thursday and Friday in Cairo to form a joint position on the conference.

The U.S. has already said the 13 nations that make up the Arab League's "follow-up committee" on a broad Arab-Israeli peace settlement are to be invited.

Aside from the Palestinians and Arab League Secretary General Amr Moussa, the committee members are Algeria, Bahrain, Egypt, Jordan, Lebanon, Morocco, Qatar, Saudi Arabia, Sudan, Syria, Tunisia and Yemen.

Only two of the countries, Egypt and Jordan, have peace deals with Israel and some, notably Syria and Saudi Arabia, remain technically at war with the Jewish state. In September, Israel is alleged to have launched an airstrike on what some reports have said was a North Korean nuclear facility in Syria.

Others expected to be invited include the members that, with the United States, make up the so-called Quartet of Mideast peacemakers _ the United Nations, European Union and Russia. Former British Prime Minister Tony Blair will also be asked to attend in his capacity as the quartet representative to the Palestinians.

Invitations may also go to select European states with a past role or interest in Mideast peacemaking such as France, Germany and Britain, along with G8 economic powers that were not covered by other invitations, such as Canada, Japan and Italy.