JERUSALEM — JERUSALEM -- Israel suffered its worst military death toll in a month of fighting in southern Lebanon as 15 soldiers were killed yesterday during ground skirmishes with Hezbollah guerrillas.
Hours earlier, as diplomats failed to forge a cease-fire agreement acceptable to both sides, the Israeli Security Cabinet approved an expansion of the army's ground offensive, heralding a possible intensification in Israel's war against the Hezbollah militant group.
Hundreds of Israeli tanks, missile launchers and other armor massed in northern Israel, firing a thunderous barrage of artillery into Lebanon as soldiers crossed the border from the Metulla area in larger numbers than in previous days.
In Lebanon's Bekaa valley, a family of seven was killed when an Israeli airstrike demolished their house. In Beirut, residents counted 10 strikes in 40 minutes yesterday afternoon.
Warning sirens wailed across northern Israel as an estimated 160 rockets rained down throughout the day. No deaths were reported in the attacks, but fields around the northern city of Kiryat Shemona were set ablaze.
Hezbollah leader Sheik Hassan Nasrallah warned Arab residents of Haifa, an ethnically mixed Israeli city on the Mediterranean coast, to leave before his fighters unleash more rockets.
The Israeli army said it was attacking al-Khiam and Marjayoun, towns in southern Lebanon, but a government spokeswoman denied that the moves marked the start of a more sweeping incursion that could extend up to 13 miles north of the border, to the banks of the Litani River.
Ten of the Israeli soldiers were killed in a battle in the border town of Debel, where Hezbollah militants used anti-tank missiles, military sources said.
The Israeli army said it killed as many as 40 Hezbollah fighters yesterday. A report on Israeli television last night said that among the militants killed were members of Iran's Revolutionary Guard, identified by papers found on their bodies. Hezbollah denied the report, which could not be independently verified. Iran and Syria are Hezbollah's main backers.
Israeli officials did not specify when a widened ground assault would begin or how many troops it would require beyond the estimated 10,000 now involved. But it could take days to ready the thousands of military reservists called up for duty last week, whose participation would be crucial for an expanded ground war.
In that time, the United Nations could achieve a resolution to halt fighting and install a peacekeeping force.
Progress on that front stalled yesterday as diplomats wrangled over the language of a draft cease-fire resolution.
At the United Nations, the five permanent members of the Security Council met into the evening yesterday but failed to bridge differences, particularly on the issue of Israeli withdrawal.
"There are areas where we are still not in agreement; there's no doubt about that," said U.S. Ambassador John R. Bolton. "But the common objective that we've had for quite some time is to create a basis for a sustainable solution that will change the environment in the region to the point where we won't have to go through this again."
A surprise visit to Beirut by U.S. Assistant Secretary of State David Welch yesterday failed to allay Lebanese concerns over the resolution.
"There is nothing new so far," Lebanese President Fouad Saniora said after the meeting, adding that he did not expect the United Nations to act within the next two days.
According to the Associated Press, the White House said yesterday that neither Israel nor Hezbollah should escalate the war. Press secretary Tony Snow said the message was for both sides, the AP reported.
In an address broadcast on the Shiite militia's television network, Nasrallah was more blunt, telling Israel, "You can enter wherever you want, but we will eject you by force. Southern Lebanon will be a graveyard for you."
Humanitarian agencies said conditions were growing increasingly desperate for Lebanese trapped in the south, some of whom have run out of food and water. Aid convoys have been unable to move into the area south of the Litani River since Sunday, when Israeli warplanes bombed the last makeshift bridge north of the port city of Tyre, Lebanon.
"It's dire," said Khalid Mansour, chief spokesman for the United Nations in Lebanon. "Basically, the south is cut off. People cannot move. We have had many villages that have completely run out of food, run out of water. We have patchy communications, and we are operating completely blind."
Israel's green light for an expanded ground assault was motivated, in part, by a desire to exert more pressure on the world body to come up with a solution, analysts said.
At the root of the decision was the recognition that four weeks of air, naval and ground operations have not significantly impaired Hezbollah's ability to stage rocket attacks from across a wide swath of southern Lebanon.
Israeli military commanders maintain that a ground offensive is essential, in part because Hezbollah guerrillas are sustained by a well-hidden network of tunnels and bunkers.
"Otherwise, what would be done?" said Uzi Ellam, an analyst at the Jaffee Center for Strategic Studies at Tel Aviv University. "We would sit there, skirmishing with Hezbollah at the front, and that's it. We would not prevent the launching of the Katyushas to the north."
Some officials said the assault could last a month. Others were less optimistic.
"Personally, I fear this will take much longer," said Eli Yishai, a member of Israel's Security Cabinet who, out of concern about more casualties, was one of three abstaining from the vote to approve a widened offensive. Nine Cabinet members voted in favor and none against after a six-hour closed-door debate.
Henry Chu, in Jerusalem, and Kim Murphy, in Beirut, write for the Los Angeles Times.