QANA, Lebanon (AP) – Thousands of civilians trapped for nearly three weeks in south Lebanon’s war zone streamed north Monday by truck, car and on foot, seizing the chance to flee during a brief halt in Israeli airstrikes. Israel’s prime minister said there would be no cease-fire in the fight against Hezbollah.

Prime Minister Ehud Olmert had agreed to the 48-hour pause beginning at 2 a.m. Monday while the military concluded its inquiry into the attack on the south Lebanese village of Qana, Israel’s deadliest strike since the conflict erupted June 12.

But Israel left open the option of striking targets to stop imminent attacks or if the military completed its inquiry. After Hezbollah guerrillas hit an Israeli tank near the village of Taibeh with an anti-tank missile, Israel said, the army carried out the airstrikes to protect ground troops.

In a second airstrike around the port city of Tyre, Israel accidentally killed a Lebanese soldier when it hit a car it believed was carrying a senior Hezbollah official. Instead, the car carried a Lebanese army officer and soldiers. “They were, of course, not the targets and we regret the incident,” the Israeli army said.

Another airstrike hit the main Lebanese-Syrian border crossing for the third time in as many days, the army and witnesses said. Israel said the strike targeted a truck importing weapons from Syria. It said the strike was in Lebanese territory.

But Lebanese police officials said two missiles struck near a vehicle carrying relief supplies near the customs post at Masnaa, wounding four people and a customs officer. The officials spoke on condition of anonymity because they were not authorized to release information to the press.

Later, Olmert continued to defy international pressure for a cease-fire, saying that fighting would end only when Israel recovers the two soldiers Hezbollah guerrillas captured in the cross-border raid that sparked the current crisis.

“We are determined to succeed in this struggle,” Olmert said. “We will not give up on our goal to live a life free of terror.”

In Washington, President Bush stuck to his position that any cease-fire be accompanied by a wider agreement addressing the root causes of the fighting, such as Hezbollah’s control of southern Lebanon, and Iran and Syria’s influence in Lebanon.

The brief pause in airstrikes meant the first relative relief for thousands of Lebanese hiding in their homes, in schools or hospitals in the dozens of villages that dot the mountainous south. Huge numbers had fled already, and those left were mostly elderly, sick or too afraid of Israeli bombardment to risk the drive.

Early Monday, few southerners had ventured out, likely questioning whether news of the cease-fire was true. By early afternoon, roads from villages into the port city of Tyre, then north from Tyre along the coast, were packed. With many of the main roads shattered, cars used dirt side roads, with white flags fluttering out windows or white sheets covering the roofs.

Mehdi al-Halim, 73, stumbled as he tried to walk out of the ruins of the border town of Bint Jbail, scene of the war’s bloodiest ground fight. He had his wife had been hiding in their home since the start of Israeli airstrikes.

“We had no food, no water. Everyday we had only one candy each, one candy that is all,” he said, grabbing his loose trousers, held together with a pin, to show the weight he had lost. “How much you eat in one day is how much we have eaten in 20 days.”

Lebanese Red Cross teams escorted by U.N. observers went to the village of Srifa to dig out more than 50 bodies believed still buried under rubble since Israeli strikes wiped out a neighborhood July 19. The bodies have begun decomposing, the Red Cross said.

Some U.N. and Red Cross aid convoys were forced to turn back from destinations in Lebanon because of continued fighting, though other trucks pressed on in an attempt to reach Qana, U.N. officials said.

The stunning bloodshed in Qana increased international pressure on Washington to back an immediate end to the fighting, and pushed American peace efforts to a crucial juncture as fury flared in Lebanon. The Beirut government said it would no longer negotiate over a U.S. peace package without an unconditional cease-fire.

Olmert repeated Israel’s regret for the civilian deaths.

“I am sorry from bottom of 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.”

Egyptian President Hosni Mubarak warned that the entire Middle East peace could collapse because of Israel’s fighting in Lebanon. “There is an urgent need for an unconditional cease-fire, which would pave the way for international efforts to end the crisis and deal with its consequences,” he said in a nationwide TV address.

Fighting was heavy in the northeast corner of south Lebanon around Taibeh and other border villages, where Israeli ground forces have been fighting Hezbollah guerrillas for nearly two weeks. Constant Israeli artillery blasts _ not covered under the air halt _ shook the hills.

Hezbollah guerrillas fired mortars at Misgav Am, near the Israeli town of Kiryat Shemona, in what was initially thought to be a rocket attack, the Israeli army said. No casualties or damage was reported.

By 4:30 p.m. Monday, no Hezbollah rockets had hit the region, a remarkable turnaround for an area hit by dozens of missiles a day during the offensive. 0verall, the suspension of airstrikes also brought relative quiet to much of southern Lebanon.

Israel called the 48-hour halt under U.S. pressure amid worldwide outrage over the Qana strike Sunday morning; of those killed, at least 34 were children and 12 women. Before, the largest death toll from a single Israeli strike was about a dozen.

It was the deadliest single attack in the Israeli onslaught against Lebanon, aimed at reining in Hezbollah, which sparked the conflict by capturing two Israeli soldiers and killing three in a cross-border raid July 12.

Some 519 people have been confirmed killed by Lebanon’s Health Ministry since the fighting began. On the Israeli side, 33 soldiers have died, and Hezbollah rocket attacks on northern Israel have killed 18 civilians, Israeli authorities said,

The attack prompted U.S. Secretary of State Condoleezza Rice to cut short her Mideast mission to return home Monday. In a nationally televised speech before leaving Israel, Rice said she would seek international consensus for a cease-fire and a “lasting settlement” in the conflict through a U.N. Security Council resolution this week.

But Israeli Defense Minister Amir Peretz said Israel plans to “expand and strengthen” its attack on Hezbollah. Israel’s top ministers were to discuss widening the army’s ground operation at a meeting later Monday, while thousands of reserve soldiers trained for the possibility of being sent into Lebanon.

It was unclear whether the senior ministers would approve a broader ground assault, defense officials said, speaking on condition of anonymity because they were not authorized to give information to the media.

Over the weekend, Olmert told Rice that Israel would need 10 to 14 more days to finish its offensive, and Justice Minister Haim Ramon told Army Radio on Monday that he did not think the fighting was yet over.

“I’m convinced that we won’t finish this war until it’s clear that Hezbollah has no more abilities to attack Israel from south Lebanon. This is what we are striving for,” Ramon said.