Condoleezza Rice has put the blame on Hezbollah for the crisis with Israel and said a cease-fire would only be possible if two kidnapped Israeli soldiers were freed.
"Any peace is going to have to be based on enduring principles and not on temporary solutions," said Condoleezza Rice after meeting Tzipi Livni, Israel’s foreign minister, in Jerusalem.
Rice offered sympathy for the Israeli people as fighting raged between their armed forces and the Shia group, Hezbollah, on the eve of her talks with Ehud Olmert, the Israeli Prime Minister, and Mahmoud Abbas, the Palestinian president.
Washington is arguing that UN resolution 1559 and the Taif Agreement, which ended the Lebanese civil war in 1990, need to be fulfilled.
Both documents call for the Lebanese government to exercise full control over its territory, and the disarmament of militias -including Hezbollah.
The United States also accuses Syria and Iran of sponsoring Hezbollah, which Washington considers a terrorist group.
Livni said: "The free world is facing a threat, the goal of Hezbollah is to set the world aflame and we will not let them succeed."
"There is no conflict between the people of Israel and the people of Lebanon, but Israel has no higher responsibility than to protect its citizens."
A few hours earlier, Rice was in Beirut, where she told Fouad Siniora, the Lebanese prime minister, that there could be no cease-fire until Hezbollah released the two Israeli soldiers it captured on July 12, sparking harsh Israeli reprisals.
A Lebanese source quoted Rice as saying that the pair would have to be released unconditionally and Hezbollah forces moved about 20km from the border.
"The tone of the meeting was very negative," the source added.
Siniora has repeatedly called for an immediate cease-fire since fighting began 13 days ago.
He has said only a broad political deal -including a prisoner swap and an Israeli pullout from the disputed Shebaa Farms area- will work.
Later during her visit, Rice told Nabeeh Berri, the Lebanese parliament speaker, that a cease-fire must be part of a deal that includes Hezbollah’s withdrawal beyond the Litani River, 20kms north of Israel, and the deployment of an international force in the border region.
She told Berri: "the situation on the border cannot return to what it was before July 12", referring to the day Hezbollah seized two Israeli soldiers during a raid into Israel, sparking a war in which 400 people have died on both sides, most of them Lebanese civilians.
Berri, a Shia close to Hezbollah insisted that there should be a sequence of events: "cease-fire, exchange of prisoners, and then discussing all other matters", a Lebanese source said.
"We knew this when we came in, but the immediacy of being in Beirut makes it very, very clear, there are some serious humanitarian problems"
David Welch, the US assistant secretary of state, who is traveling with Rice, said his country would "contribute $30 million" in humanitarian assistance to Lebanon.
The US aid package comes on the heels of a UN appeal for $150 million to help 800,000 Lebanese citizens made homeless by Israel’s offensive against Hezbollah.
"We knew this when we came in, but the immediacy of being in Beirut makes it very, very clear, there are some serious humanitarian problems," Welch said.
On Wednesday, Rice will go to Rome to discuss the crisis with European and Arab foreign ministers.
Kofi Annan,, the United Nations secretary general, said that he would press for a truce and the establishment of an international peacekeeping force at the meeting.
Israel has dropped its objections to the force and several European Union nations have said they will contribute troops, but EU officials also said that questions remained over how it could fulfill its mission.
Britain has backed the use of an international force as a "buffer" between Hezbollah and Israel.
But he has been under political pressure in Britain for joining the President Bush in not publicly calling for an immediate cease-fire.
Although Blair has been one of the prime backers of an international force, Britain is unlikely to contribute to one because of military commitments in Iraq and Afghanistan.
NATO reacted cautiously to calls for it to lead the peacekeeping force and diplomats pointed out that the military alliance was already hugely stretched, notably in Afghanistan.
"There are huge challenges involved for any kind of intervention force," said one NATO source in Brussels.
The North Atlantic Treaty Organization in theory has the command structure, planning capability and political coordination capability to run a multi-national operation, said the source.
But he added: "What (NATO) allies are willing to put at its disposal is a different question."
The Washington Post reported that France and Turkey could provide a significant number of troops, but NATO sources said getting enough fire power would be a "huge challenge."