Secretary of State Condoleezza Rice on Wednesday called on the international community to work on solutions for sustainable peace in the Middle East, insisting that there can be no return to the status quo of political uncertainty and instability in Lebanon.

"There is much work to do and everyone has a role to play," Rice told reporters at a joint press briefing attended by U.N. Secretary-General Kofi Annan and other leaders taking part in a daylong conference on the Mideast crisis in Rome.

Rice said she told her counterparts that "we all want" an end to the violence. But Rice added that the U.S. was seeking “a plan that will actually create conditions in which we can have a cease-fire that will be sustainable."

Her wording suggested continued U.S. support for Israel's demand that the violence must end with the Hezbollah militia disarmed or at least removed from its border.

That position has set the United States, as well as Britain, apart from most of the others at the table — who, while supporting the goals, want Israel's devastating offensive to end first.

The policy conference, called after two weeks of fighting between Israel and the Hezbollah guerrillas, ended with a call to end the violence and the establishment of an international force to keep the peace — but they did not unanimously call for an immediate cease-fire or provide details on the proposed force.

Hundreds of Lebanese have been killed and more than half a million more have become refugees since the conflict began. Hezbollah has inflicted dozens of Israeli casualties by firing hundreds of rockets into northern Israel and in firefights with Israeli troops.

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The United States has staunchly opposed any unconditional cease-fire being called for by other nations and Annan. In two days of diplomacy in Lebanon, Israel and the West Bank, Rice rejected a "quick fix" and raised doubts about the effectiveness of an immediate cease-fire.

Rice told the news conference that Syria has an obligation under an existing United Nations resolution to support "a fully sovereign Lebanon that indeed can control all the armaments in the country."

Earlier, Lebanese Prime Minister Fuad Saniora gave an impassioned speech that prodded the international leaders to continue working, Rice said, saying he put "a human face" on the crisis.

"The more we delay the cease-fire, the more we are going to witness more being killed, more destruction and more aggression against the civilians in Lebanon," Saniora said in his address.

The Rome conference appears to have formalized the numerous proposals to establish a new multinational force for southern Lebanon — one far tougher than the existing, three-decade-old UNIFIL operation, which has lacked a mandate to prevent hostilities.

Rice told reporters: "What we agreed upon is that there should be an international force under a U.N. mandate that will have a strong and robust capability to help bring about peace, to help provide the ability for humanitarian efforts to go forward and to bring an end to the violence."

But Rice conceded that it would take further meetings for countries to agree on details on precisely how that force would operate and what its mission would be.

"I think the mandate of the security forces will be discussed over the next several, several days," Rice added. "We also have asked that those meetings be held urgently so that the force can be put together."

Annan appealed for nations to come forward with commitments to contribute troops for a force "that may eventually be sent to the region to help stabilize southern Lebanon to allow the government of Lebanon time and space to prepare its own troops and be able to extend its authority throughout the country."

There was no immediate response from Israel, which did not attend. Israeli officials have expressed support in principle for the deployment of an international force, recognizing that the weak Lebanese government could not likely subdue the Iranian- and Syrian-backed Hezbollah without assistance.

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The secretary of state said that she and her counterparts all agreed, additionally, to continue moving quickly on humanitarian assistance.

Rice said she had had private discussions with Saniora here — and separately with Israeli Prime Minister Ehud Olmert — but declined to reveal the details.

"The goal here is to see how the United States can contribute to end this violence so the Lebanese people and the Israeli people can live in peace," she said.

The Associated Press contributed to this report.