US Secretary of State Condoleezza Rice has ended a Middle East tour without firm commitments to a conference on the Israel-Palestinian conflict.

But she said the talks, due to be held in the US by the end of the year, still had a "reasonable chance of success".

Palestinian President Mahmoud Abbas accused Israel of holding up a joint document with the Palestinians.

He said time was running out and the Palestinians could opt out of the conference without the document.

The Israelis are pushing for a more general framework.

'Blame game'

Mr Abbas, who effectively only controls the West Bank since his Palestinian rivals Hamas seized power in the Gaza Strip, said: "It's impossible to go to the conference at any price.

"We told Secretary Rice we don't have much time, that we must make use of every minute."

After four days of shuttle diplomacy, Ms Rice said the US did not itself expect "anybody to attend [the conference] at any cost", America included.

"We are at the beginning of a process," she said at a joint news conference with Israeli Foreign Minister Tzipi Livni after talks in Jerusalem.

"If we work hard to resolve these issues, I think we have a reasonable chance of success in moving forward on the vision of two states living side by side in peace and freedom."

Ms Livni said she did not want to take part in a "blame game".

Israeli, she said, wanted "to reach understanding on the widest possible common ground in the time available".

Ms Rice, who arrived in the region on Sunday, also held "fruitful" talks with Egyptian President Hosni Mubarak in Cairo during her trip.

The conference is set to be held in Annapolis, Maryland.