Lebanese fled north in overflowing trucks and cars Monday, taking advantage of a lull in Israeli bombardment. Israel's prime minister took a tough line, apologizing for the deaths of dozens of Lebanese civilians in a single strike but declaring there will be no cease-fire.

A photograph of Du Zhaoyu is displayed at a memorial service in Jerusalem for the four UN observers killed in Lebanon.  [Xinhua]

Diplomatic efforts to end the crisis faltered, despite increased world pressure for a cease-fire after the devastating strike in Qana.

Israeli warplanes hit Hezbollah fighters battling with soldiers near the border as the guerrillas fired mortars into Israel. The clashes signaled that the violence was not over, even though an Israeli suspension of most airstrikes in Lebanon ¡ª and a pause by the guerrillas on rocket attacks in northern Israel ¡ª brought both countries their quietest day since the conflict began three weeks ago.

Some 200 people ¡ª mostly elderly ¡ª escaped the Lebanese border town of Bint Jbail, where Israeli troops and Hezbollah guerrillas fought their bloodiest clashes. Two residents dropped dead on the road out, one of malnutrition, the other of heart failure.

Some survivors described living on a piece of candy a day and dirty water as the fighting raged.

"All the time I thought of death," said Rimah Bazzi, an American visiting from Dearborn, Mich., who spent weeks hiding with her three children and mother in the house of a local doctor.

The lull was felt across northern Israel, too: In the town of Nahariya, residents who had been hiding in shelters for the better part of three weeks began emerging. Supermarkets were fuller than before and more people were in the streets, walking along the beach and shopping.

Israeli Prime Minister Ehud Olmert apologized for the civilian deaths in Saturday's strike, in which 56 people, mostly women and children, were killed.

"I am sorry from the bottom of my heart for all deaths of children or women in Qana," he said. "We did not search them out. ... They were not our enemies and we did not look for them."

But he insisted Israel had no choice but to fight.

"There is no cease-fire, there will be no cease-fire," he said. "We are determined to succeed in this struggle. We will not give up on our goal to live a life free of terror."

Near the fighting, grass fires set by shelling blazed into the night sky from the hills outside the Lebanese border town of Marjayoun. U.N. peacekeepers struggled to get trucks full of aid supplies across the Litani River as artillery pounded only a few hills away.

President Bush resisted calls for an immediate halt to fighting, underlining that any peace deal must ensure that Hezbollah is crippled. He said Iran and Syria must stop backing the Shiite militant group with money and weapons.

"As we work with friends and allies, it's important to remember this crisis began with Hezbollah's unprovoked attacks against Israel. Israel is exercising its right to defend itself," Bush said.

Secretary of State Condoleezza Rice earlier in the day said she expected a U.N. resolution for a cease-fire within a week. But as she headed to Washington after a visit to Jerusalem derailed by the Qana strike, she struck a more pessimistic tone.

"There's a lot of work to do," she told reporters. "You have to get all the work done, you have to get it done urgently."

The central focus for a peace deal has been the deployment of a U.N.-mandated international force in southern Lebanon to ensure guerrillas do not attack Israel. But details of the force still must be worked out. With talks continuing, the U.N. postponed a Monday gathering meant to sound out contributions to a force.

Hezbollah's allies Syria and Iran quietly entered the diplomacy. Egypt was pressing Syria not to try to stop an international force in the south, diplomats in Cairo said. Iran's foreign minister pulled into Beirut for talks with his French and Lebanese counterparts.

Syrian President Bashar Assad called on his army Monday to increase readiness to cope with "regional challenges." Travelers from Syria have reported that some reservists have been called up for military duty ¡ª a sign that Syria is concerned the fighting in Lebanon could spill over.

Israel's Security Cabinet met Monday night to discuss the army's request for a wider ground offensive in southern Lebanon. The Israeli onslaught was sparked when Hezbollah snatched two soldiers and killed three others in a cross-border raid July 12.

Israel called a 48-hour suspension of airstrikes after the Qana strike to give time for an investigation ¡ª though it said its warplanes would still hit urgent Hezbollah targets, and at least three strikes took place Monday.

Thousands of Lebanese took advantage of the lull to make a dash for safety farther north after weeks trapped in homes in the war zone, afraid to move because of intense missile strikes on roads.

Across the south, cars and trucks packed with women and children, mattresses strapped to the roofs and white flags streaming from the windows, made their way to the coast, then turned north. They passed flattened houses, shattered trees and burned-out cars strewn on the roadside.

At one point north of Tyre, vehicles gingerly made their way around a gigantic crater half filled with water into which a car had toppled when a missile struck.

In Qana, grocer Hassan Faraj ¡ª who had sworn a day earlier never to leave ¡ª jumped at the chance to escape. He shuttered his shop and loaded his wife and child into a van to go north into the mountains.

"My mother is very unwell, I must go and see her," he said, explaining his change of mind and insisting he was just dropping off his family to return.

Aid groups were caught off guard by the sudden break and struggled to rush aid to the south.

Outside Marjayoun, a U.N. peacekeepers' convoy carrying food found the bridges across the Litani destroyed. So the trucks drove across the knee-deep waters. Indian peacekeepers assembled a ramp out of stones to get them up the steep opposite bank.

Nearby, the battle raged between guerrillas and soldiers. Warplanes struck around the village of Taibeh to give ground cover after Hezbollah fighters hit a tank with an anti-tank missile. The guerrillas also fired mortars into the nearby Israeli town of Kiryat Shemona, causing no casualties.

Hezbollah announced that five of its fighters were killed in the clashes, bringing the group's acknowledged death toll to 43. Israel says dozens more fighters have died.

Israel carried out two other airstrikes. One killed a Lebanese soldier in his car outside Tyre, prompting Israel to express its regrets, saying it had believed the vehicle was carrying a senior Hezbollah official. The other strike hit the main Lebanon-Syria border crossing for the third day in a row.

Hezbollah also claimed to have hit an Israeli warship off the coast of Tyre with a rocket, the second hit it would have scored on a ship. But Israel denied any of its warships were hit Monday.

The guerrilla group did not shoot a single rocket into Israel as of early evening, a remarkable turnaround for an area that had been hit by dozens of missiles each day during the offensive.

At least 524 people have been killed in Lebanon since the fighting began, according to the Health Ministry. Fifty-one Israelis have died, including 33 soldiers and 18 civilians who died in rocket attacks.

After Rice's intense diplomatic mission in the Mideast, efforts to put together a peace package now turned to the United Nations.

She said the U.S. will work to achieve a U.N. resolution on three fronts: the precise language of the U.N. resolution, working with Lebanon and Israel on the details of tough political questions and an agreement that leaves no ambiguity in the international force's role and operations.