BOURJ AL-MULOUK, Lebanon -- Heavy ground fighting raged Tuesday near a border village and Israel resumed frequent airstrikes after it decided, in a major expansion of its offensive, to send thousands more troops deeper into Lebanon.
The soldiers will go as far as the Litani River, 18 miles from the Israeli border, to clear out Hezbollah fighters and hold the territory until a multinational force is deployed there, senior Israeli officials said Tuesday.
The resumption of the Israeli air campaign against Hezbollah strongholds and supply routes came despite an earlier pledge to suspend such attacks for another day. That 48-hour suspension was announced after the world expressed outrage over the killing of 56 Lebanese -- mostly women and children -- in a weekend Israeli bombing.
Israeli Prime Minister Ehud Olmert said Tuesday that it was not in Israel's interest to agree to an immediate cease-fire because every day of fighting weakens Hezbollah.
Three Lebanese civilians were killed and three more were seriously wounded when Israeli warplanes hit a house in the southern town of Lweizeh on Tuesday evening, Lebanese security officials said.
The Lebanese Red Cross said it retrieved 12 bodies buried in the rubble of four villages flattened by Israeli airstrikes in south Lebanon. It was unclear when they died. Workers were still digging through the wreckage and said they expected to find more bodies.
Intense gun battles also were reported in several south Lebanon villages, and Hezbollah said four of its fighters were killed. The guerrilla group claimed that 35 Israeli soldiers had been killed or wounded in the fighting, but Israel had no immediate public comment.
The heaviest fighting centered on the Lebanese border village of Aita al-Shaab. Arab satellite channels carried live pictures as Israeli forces unleashed a relentless bombardment of artillery shells on the town, from which Hezbollah guerrillas crossed the border on July 12 and captured two Israeli soldiers, sparking the crisis.
Diplomatic efforts to end the crisis have faltered, despite increased world pressure for a cease-fire after the devastating weekend strike in the town of Qana.
Olmert expressed hopes that a cease-fire would be based on a formula that would push Hezbollah away from Israel's border and prevent it from attacking in the future.
"We are at the start of a diplomatic process that I believe will lead in the end to a cease-fire under totally different conditions from those which existed previously on our northern border ... which will provide a real buffer between us and those who would take our lives, with international support such as there has never been before," he said.
"We ... will agree to a cease-fire when we know for certain that conditions in the field have changed from those that would cause a war to break out," he said.
President Bush also resisted calls for an immediate halt to fighting, saying 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.
Israel made the decision to expand the ground offensive at a meeting late Monday of its Security Cabinet.
Up to now, several thousand soldiers had been engaged, fighting house-to-house battles with hundreds of Hezbollah fighters in Lebanese towns and villages close to the border. Last week, the Cabinet called up some 30,000 reserve soldiers, many of whom reported to their bases earlier this week to begin training.
Defense officials said they expected thousands more soldiers to be sent to Lebanon.
"We have reached the stage where we have to expand the operation," said Defense Minister Amir Peretz, without giving the dimensions of the next phase.
Labor Party lawmaker Danny Yatom confirmed the Security Cabinet approved a ground offensive up to the Litani River. The goal is "to control the area, to kill as many Hezbollah terrorists as possible and to destroy as many rockets and launchers as possible, in order to minimize the capabilities of Hezbollah," Yatom, a reserve general and former chief of the Mossad spy agency, told The Associated Press.
The Litani meanders through south Lebanon, and at some points is as far as 18 miles from the Israeli-Lebanese border. A 1978 incursion by Israel into Lebanon, to push back Palestinian guerrillas, was named after the river.
Justice Minister Haim Ramon, a member of the Security Cabinet, said he hoped the push would be completed in 7-10 days to create the conditions for a multinational force to deploy there. Another Cabinet minister, Binyamin Ben-Eliezer, said he expected the offensive to take up to 14 days.
Peretz said Israel would target vehicles carrying weapons from Syria to Lebanon but reiterated that Israel was not trying to draw Syria into the war. Israel has repeatedly accused Syria of allowing Iranian-made weapons to be shipped through its territory to Hezbollah guerrillas in Lebanon.
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 sign that Syria is concerned the fighting in Lebanon could spill over.
Israel said it would investigate the Qana attack, but army officials said Tuesday they did not know when findings would be released. Olmert apologized for the civilian deaths.
"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."
As part of a truce deal, a U.N.-mandated international force would be deployed in southern Lebanon to ensure guerrillas do not attack Israel. But details of the force still must be worked out.
Israel wants a strong, armed force with a mandate to confront militants, and Ramon reiterated Tuesday that Israel seeks NATO involvement. Israel feels U.N. peacekeepers, deployed in south Lebanon since 1978, are at best useless.
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.