Saudi Arabia – potentially a key player in current diplomatic moves on the Middle East – has warned that Fatah and Hamas will have to form a new coalition if any peace accord between Israel and the Palestinians is going to work.

At the same time it has expressed cautious optimism about the international Middle East conference called by George Bush for November – without yet committing itself to attend, as Israel and the United States would like it to.

The latest, relatively candid, summary of the Saudi position came during the meeting of the UN General Assembly in New York on the fringes of which the Saudi Foreign Minister, Prince Saud al-Faisal, met the US Secretary of State, Condoleezza Rice, and top officials from Gulf states.

Meanwhile President Hosni Mubarak of Egypt and King Abdullah of Jordan issued a joint statement calling on the Palestinians to "adopt unified stances that would... enable them to establish their independent state and restore their national legitimate rights".

The Egypt-Jordan statement stopped well short of explicitly calling for the re-formation of the short-lived unity coalition government, which was dissolved by the Palestinian President, Mahmoud Abbas, after Hamas's takeover of Gaza followed several days of bloody infighting in June.

The US, which opposed the idea of the unity government, and Israel have described its collapse and the creation by Mr Abbas of an emergency government in the West Bank as the "opportunity" that has opened a possibility of an accord between Mr Abbas and the Israeli Prime Minister, Ehud Olmert, on a future two-state solution to the conflict.

Prince Saud, part of the government the brokered the coalition deal in Mecca, said that for any peace deal between Israelis and Palestinians to work, Hamas and Fatah must join in another national unity government. The prince also said that Israel should cease work on the 450-mile separation barrier and halt expansion of Jewish West Bank settlements to assure Arab leaders it is serious about peace.

He said that if the international community had backed the national unity government when it was agreed in February, Hamas might have eventually renounced violence against Israel. That was "water under the bridge now", he said, adding: "Peace can not be made by one man or by half a people."

Saudi Arabia, along with Egypt and Jordan, have strongly backed Mr Abbas's insistence that the conference tackle the so-called final status issues, including Jerusalem and the fate of families of Palestinians who fledin 1948. Israel, however, says the focus should rather be on identifying "common ground".

* Israel's Foreign Ministry last night denied a report in a Nazareth weekly, Al Sinara, that Tzipi Livni, the Israeli Foreign Minister, had met in New York for an hour with her Syrian counterpart, Walid Moallem.