Diplomatic efforts to stop the weeklong conflict between Israel and Lebanon gained momentum, but Israel said it was preparing to fight Hezbollah terrorists for several move weeks and might send in ground forces.

At daybreak Wednesday, a small number of Israeli troops were operating just across the border, looking for tunnels and weapons, the military said.

Early Wednesday, explosions were heard in southern Beirut, and Beirut TV stations reported strikes in two towns and a bridge in southern Lebanon. No casualties were reported in the latest strikes.

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On Tuesday Israeli warplanes struck an army base outside Beirut and other areas in south Lebanon, killing 17 people, and Hezbollah rockets battered towns across northern Israel, killing one person.

Hundreds of Europeans and Americans fled Lebanon aboard ships, and hundred of other foreigners prepared to evacuate in the coming days. However, evacuation of U.S. citizens 25,000 on a cruise ship was delayed a day. The ship docked early Wednesday, and boarding was to begin at dawn, as U.S. officer said.

Families in southern Lebanon, the site of most Israeli airstrikes, drove north on side roads, winding among the orange and banana groves and waving improvised white flags from their car windows.

In diplomatic efforts to end the fighting, which has killed at least 227 people in Lebanon and 25 in Israel, a U.N. mediation team met Tuesday with Israeli leaders a day after speaking with Lebanese officials in Beirut.

Foreign Minister Tzipi Livni, who met with the delegation, said a cease-fire would be impossible unless the soldiers captured by Hezbollah in a cross-border raid last week were released and Lebanese troops were deployed along the border with a guarantee that Hezbollah would be disarmed.

Prime Minister Ehud Olmert told diplomats that he does not oppose negotiations, but the solution must be based on freedom for the two soldiers and implementation of a Security Council resolution that calls for disarming Hezbollah and posting the Lebanese army on the border, according to a statement from his office.

Later Tuesday, meeting mayors from Israel's battered border communities, Olmert said Israel would not allow the previous situation of Hezbollah, armed with thousands of rockets controlling south Lebanon, to be restored.

"Does anyone imagine that we will stop halfway through so that in two months it will come back again? No way," he said.

In Washington, U.S. Secretary Condoleezza Rice said that any cease-fire should be based on fundamental changes that would have a lasting impact on the region.

"We all want a cessation of violence. We all want the protection of civilians. We have to make certain that anything that we do is going to be of lasting value," Rice said.

The week-old offensive was sparked by the soldiers' capture, and Olmert said Iran, a patron of Hezbollah, was behind the raid to distract the world and the G-8 summit from the country's nuclear program. "To my regret, Iran's trick succeeded, everybody remembers the G-8 decision on the subject of Lebanon and are not dealing with the Iranian issue," he said, according to the statement.

The commander of Israeli forces on the border said the operation would take a few more weeks, and the army's deputy chief of staff, Maj. Gen. Moshe Kaplinski, said Israel has not ruled out deploying "massive ground forces into Lebanon."

Israel, which has mainly limited itself to attacks from the air and sea, has been reluctant to send in ground troops because of still-fresh memories of Israel's ill-fated 18-year-occupation of south Lebanon that ended in 2000.

Meanwhile, a proposal to send a new international force to bolster the current 2,000-member U.N. force in south Lebanon gained steam.

Western nations have proposed the beefed-up force as part of a possible cease-fire agreement, and U.N. Secretary-General Kofi Annan said Tuesday in Brussels, Belgium, that a new force must be "considerably" larger and better armed than the current force, which is viewed as weak and ineffectual. Rice also called for the introduction of a strong peacekeeping operation.

In the statement, Olmert belittled the current force in Lebanon, but said he would be cautious about discussing the new force. "It seems to be its too early to debate it," he said.

As the diplomatic efforts continued, the Israeli air force kept up its strikes across southern Lebanon, hitting a military base at Kfar Chima before dawn Tuesday as soldiers rushed to their bomb shelters, killing at least 11 soldiers in an engineering unit and wounding 35 others, the Lebanese military said. The base is in a hilly area next to Hezbollah strongholds in southern Beirut that were frequently targeted by recent Israeli strikes.

Lebanese Defense Minister Elias Murr denounced the strike as a "massacre," saying the regiment's main job was to help rebuilt damaged infrastructure. The Lebanese army has largely stayed out of the fighting, confining itself to firing anti-aircraft guns at the Israeli planes. But Israeli jets have struck Lebanese army positions.

At least five people also were killed when a bomb hit a house in the village of Aitaroun, near the border, witnesses said. Israeli warplanes hit four trucks that Israel said were bringing weapons into Lebanon.

Capt. Jacob Dallal, an Israeli army spokesman, denounced the shipments. "That is intolerable terrorist activity," he said. "They are using civilian infrastructure to bring in weapons, which they are using against us and killing Israelis, and we will exercise our right of self defense to stop the flow of weapons into Lebanon."

Syrian Vice Foreign Minister Fayssal Mekdad denied the charge. "We don't supply Hezbollah with weapons, and Hezbollah does not want or need our weapons," he told CBS Evening News with Bob Schieffer.

Hezbollah guerrillas fired a new barrage of rockets into northern Israel on Tuesday afternoon, killing a man as he walked down the street toward a bomb shelter in the town of Nahariya and setting fire to the top of a two-story apartment building.

At least 100 rockets fell into Israel, hitting a string of towns, including the city of Haifa.

More than 750 rockets have hit Israel since the violence began, forcing hundreds of thousands of Israelis to take cover in underground shelters.