US Secretary of State Condoleezza Rice has held talks in Cairo with the Egyptian President Hosni Mubarak.
US Secretary of State Condoleezza Rice has ended a Middle East tour without firm commitments to a conference on the Israel-Palestinian conflict.
Her visit is part of efforts to win support for a US-sponsored Middle East conference set for November.
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".
Ms Rice said the conference could be a success if all parties met their obligations, both before and after the planned summit.
Palestinian President Mahmoud Abbas accused Israel of holding up a joint document with the Palestinians.
Earlier she said that it was time for a Palestinian state to be founded, and that the US would press for this.
He said time was running out and the Palestinians could opt out of the conference without the document.
"There is a lot of work leading up to the meeting, and there is going to be a lot of work after the meeting in order to achieve a Palestinian state and the two-state solution.
The Israelis are pushing for a more general framework.
"But there are obligations on all sides, and the United States expects everyone to exercise them," she said.
'Blame game'
Ms Rice said her talks in Cairo had been fruitful and that although no date had yet been agreed for the conference - set to be held in Annapolis, Maryland - her meetings were giving momentum to the peace process.
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.
She said that it would have to be "a serious and substantive conference that will advance the cause of a Palestinian state".
"We told Secretary Rice we don't have much time, that we must make use of every minute."
On Monday the Egyptian Foreign Minister, Ahmed Abul Gheit, suggested delaying the conference if there were no Israeli-Palestinian agreement on a conference document.
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.
"Rushing into holding the meeting without an agreement over a substantive and positive document may damage opportunities to achieve a just peace," he said.
"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.
Ms Rice held talks on Monday with Palestinian Authority President Mahmoud Abbas in Ramallah after which she said the US would encourage Israeli and Palestinian negotiators to work intensively on the joint document for the conference.
"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."
She said the US regarded a two-state solution "as absolutely essential for the future, not just of Palestinians and Israelis but also for the Middle East and indeed for American interests".
Ms Livni said she did not want to take part in a "blame game".
The Palestinians have warned that if no tightly-worded text is agreed on which to base talks, they will not attend. The Israelis say they do not believe an agreed text is necessary.
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.
