Iran's supreme leader called on Muslim countries Saturday to boycott a U.S.-sponsored international peace conference on the Middle East, saying the meeting would hurt the Palestinians.

"Efforts are being made to once again make an imposition on the Palestinian people in the name of peace. ... The result of all conferences held in the name of peace so far have been to the detriment of the Palestinian nation," Supreme Leader Ali Khamenei said in a speech marking the end of the Muslim holy fasting month of Ramadan.

Khamenei was referring to an upcoming U.S.-hosted international peace conference on the Middle East planned for next month.

The United States has kept quiet on the most basic details about the meeting, including precise dates, the guest list and the location — though it is expected to be in Annapolis, Maryland. U.S. officials have said the November session will be a serious run at problems that have proved insoluble in the past.

But Khamenei said the conference was a "deception" that must be shun by Muslims all over the Middle East.

"When the Palestinians see this is as a deception, everybody has to see it as a deception. This U.S. initiative is an effort to save the Zionists," Khamenei said.

Iran doesn't recognize Israel and wants the establishment of a Palestinian state with Jerusalem as its capital. Khamenei, who has the final say on all state matters in Iran, has repeatedly called Israel in the past a "cancerous tumor" that need to be removed from the Middle East.

Khamenei comments come amid growing skepticism of the conference among some Arab governments, which have expressed doubts the planned gathering will tackle the main issues of the conflict with Israel.

The Bush administration has said it will invite adversary Syria to the conference, but Syrian President Bashar Assad has all but ruled out his country's participation. Egypt, Jordan and Saudi Arabia have not said whether they will attend.

The head of the Palestinian Hamas government, Ismail Haniyeh, in the Gaza Strip also has urged Arab countries not to attend the conference.

The Islamic militant Hamas, which is backed by Iran, seized power in Gaza from Fatah security forces loyal to Palestinian President Mahmoud Abbas in June. Abbas retaliated by expelling Hamas from government and setting up a Western-backed government in control of the West Bank.

"Palestinians have rejected this (conference). How can other governments attend this conference?" Khamenei said, referring to Hamas.

Abbas and Israeli Prime Minister Ehud Olmert have met every few weeks in recent months in an effort to formulate a framework for the peace talks. Palestinian negotiator Saeb Erekat has said they have come to some agreements, but he would not elaborate.