MISGAV AM, Israel -- Thousands of Israeli troops backed by armor advanced deeper into Lebanon yesterday, crossing the Litani River in the south as a smaller force mounted an operation in the Bekaa Valley between Beirut and Syria.
The ground offensive moved at least 12 miles across the border, by far the deepest such penetration in a campaign that began three weeks ago. The offensive was undertaken by the largest Israeli force assembled inside Lebanon since the outbreak of the fighting with Hezbollah guerrillas.
Clashing repeatedly with the Islamist militants and pounding southern Lebanese villages with renewed airstrikes, the Israelis undertook the broad push as a 48-hour slowdown in air attacks ended early today.
In the east-central Bekaa Valley, Israeli forces landed near Baalbek, where Hezbollah has its headquarters. Hezbollah's Al-Manar television said militants were battling an Israeli unit outside the Dar al Hikma Hospital near the city.
The Israeli military initially refused to comment but later said that it had captured several Hezbollah members in the Baalbek fighting and that all of its soldiers had returned safely to base.
Meanwhile, diplomatic efforts to stop the bloodshed faltered in the United States and Europe, humanitarian aid failed to reach many devastated Lebanese towns, and the Israeli government pledged to press ahead with a military campaign that one Cabinet minister predicted would last 10 to 14 more days.
At least three Israeli troops were killed in yesterday's fighting with Hezbollah. Israeli officials said their ground forces killed at least 20 Hezbollah militants during the latest clashes, in addition to the 250 or so killed in earlier battles. Hezbollah disputes the figures.
"Every additional day [of fighting] is a day that erodes the power of this cruel enemy," Israeli Prime Minister Ehud Olmert said last night. "Every additional day, the Israeli army reduces their ability to fire, and also their ability to strike in the future."
Israeli infantry crossed the Litani River in several spots and reached the northern edge of what Israel held as a buffer zone for 18 years until withdrawing in 2000, said Brig. Gen. Shuki Shihrur, deputy commander of the Israeli army's northern command.
Shihrur said his forces were in control of positions along the waterway, which runs roughly parallel to the border, through air and artillery power. In some areas, he said, ground forces had sped past settled areas to reach the river and beyond in a bid to prevent Hezbollah from bringing in new fighters and arms.
The goal of the ground offensive is not to conquer towns but to work southward from the river to clear Hezbollah from the border area and weaken it before any international peacekeeping force could be deployed in southern Lebanon, Shihrur said.
He estimated Israeli troop strength in the area at the equivalent of six brigades, which would be as many as 10,000 soldiers. It is the largest force assembled inside Lebanon since the outbreak of hostilities three weeks ago.
"The purpose of the mission is to control area, to hold terrain, sometimes to bypass the built-up area and to continue north," Shihrur said during a briefing last night near the border.
Hours before the intensified clashes, Israel's Security Cabinet, made up of military officials and other senior advisers to Olmert, approved a widening of Israel's ground offensive.
"I estimate the time required to complete the job will take around 10 days to two weeks," Cabinet Minister Benjamin Ben-Eliezer told Israeli army radio.
As they pushed northward, Israeli forces encountered stiff resistance from Hezbollah in several pockets.
The most intense clashes were reported in the village of Aita al-Shaab, about five miles west of where fighting was centered last week. One officer and two soldiers were killed, the Israeli military said, and at least 25 soldiers were wounded.
In addition to Aita al-Shaab, fighting raged around Maroun el-Ras, a site of earlier clashes, the army said. At the other end of the front, near the Israeli communities of Misgav Am and Metulla, the army focused its offensive against villages that Hezbollah has used for launching Katyusha rockets over the border into communities in the northern Galilee, including Kiryat Shmona.
Israeli military officials have said publicly that they hope to create a 1.2-mile-wide strip in southern Lebanon that will be free of Hezbollah fighters.
The ground combat intensified amid a relative lull in Israeli airstrikes, part of a 48-hour suspension that began early Monday and expired early today. Israel agreed to the measure under intense U.S. pressure after an Israeli bomb killed nearly 60 civilians, most of them children in the southern Lebanon town of Qana.
By early last evening, the Israeli military reported having carried out a dozen airstrikes targeting what it said were mainly rocket launchers and weapons caches.
Hezbollah fired 10 short-range Katyusha rockets and four mortar shells into northern Israel yesterday, the army said, down from as many as 150 a day during much of the 21 days of fighting.
The reprieve from Israeli bombings was intended to allow humanitarian workers to reach besieged villages. That was only partly successful, aid agencies said.
United Nations relief agencies planned convoys of water, food and medical supplies destined for the war-ravaged cities of Naqoura, Rmeish and Tebnin. But United Nations spokesman Khaled Mansour said Israeli authorities approved only the trip to Tebnin.
There was little progress in efforts by diplomats to end the fighting.
"An immediate cease-fire is something that at this point doesn't seem to be in the cards," White House spokesman Tony Snow said yesterday.
At the United Nations, Secretary General Kofi Annan was forced to postpone a meeting to discuss an international peacekeeping force for the region, while he beseeched the five Security Council countries with veto power to put aside their differences in the interest of resolving the crisis.
Ken Ellingwood writes for the Los Angeles Times.