BEIRUT, Lebanon, AP -Israel’s pounding of Hezbollah positions across Lebanon expanded Friday with missiles targeting bridges in the Christian heartland north of Beirut for the first time. A top U.N. aid official said air strikes on the main north-south highway risked cutting off Lebanon’s “umbilical cord” to the world.

Four civilians were killed and 10 wounded in the air raid, the Lebanese Red Cross said. A Lebanese soldier and four civilians were also killed in air raids near Beirut’s airport and southern suburbs, security officials and witnesses said.

Another strike slammed into farm workers loading vegetables into a refrigerator truck near the Lebanon-Syria border later Friday, killing or wounding as many as 40 people, the workers’ foreman said.

The Lebanese and Kurdish farm laborers were in a field in a strip of no-man’s land along Lebanon’s eastern border with Syria, foreman Rabei al-Jabali said.

He said casualties were taken to a hospital in Syria, because roads in Lebanon were cut off by earlier airstrikes.

The broadened bombing came as Hezbollah hammered Israel with more than 120 rockets Friday, killing two people, a day after Hezbollah’s leader offered to stop the attacks if Israel ends its airstrikes.

Israel’s United Nations ambassador, Dan Gillerman, said that Sheik Hassan Nasrallah’s offer of a truce was “a sign of weakness … and he may be looking for a way out.”

Gillerman warned against Hezbollah threats to launch rockets on Israel’s commercial center of Tel Aviv. “We are ready for it, and I am sure that he (Nasrallah), as well as his sponsors, realize the consequences of doing something as unimaginable and crazy as that,” the Israeli ambassador told CNN.

The destruction of four bridges on the main north-south coastal highway linking Beirut to Syria contributed to further seal Lebanon from the outside world Friday, as the Israeli naval blockade — along with earlier strikes against the road to the eastern boarder and the capital’s international airport — have largely closed off other access points.

The strikes against the northern highway hindered means of bringing relief supplies into Lebanon, international aid agencies said Friday.

“This is Lebanon’s umbilical cord,” Christiane Berthiaume of the World Food Program told AP. “This (road) has been the only way for us to bring in aid.”

A convoy that was meant to carry supplies and emergency personnel to Beirut on Friday is now stuck, she said, and U.N. teams have so far been refused permission to assess the damage caused by the bombing. She added that U.N. trucks might be able to take secondary roads, but this would slow down aid shipments.

Portugal on Friday put a cargo plane at the U.N.’s disposal, which will fly food and medicines from Italy to Beirut once a day for four days. Israel has given permission for these flights to start immediately, said Berthiaume. A Greek boat will ferry supplies from Italy, starting Saturday, she said.

An Israeli army spokesman, Capt. Jacob Dallal, said Israel targeted the bridges to stop the flow of weapons from Syria.

“Our attacks last night were aimed at stopping the flow of weapons to Hezbollah,” Dallal said.

Lebanese President Emile Lahoud said the strikes showed Israel was waging a “war of starvation” against Lebanon.

“The Israeli enemy’s bombing of bridges and roads is aimed at tightening the blockade on the Lebanese, cutting communications between them and starving them,” Lahoud said in a statement issued Friday.

He said Israel was trying to pressure Lebanon to accept its conditions for a cease-fire, which include Hezbollah’s disarmament and ouster from a swath of south Lebanon.

Meanwhile, fierce fighting continued along the border, and Hezbollah said in a statement broadcast by the group’s Al-Manar TV station that guerrillas had killed several Israeli soldiers near the villages of Aita al-Shaab and Markaba.

The Israeli army confirmed a Hezbollah anti-tank missile killed two soldiers and wounded two others in southeastern Lebanon Friday.

The latest attacks in the southern Beirut suburb of Dahieh targeted Hezbollah facilities and a Hamas office, the Israeli military said. Beirut media said Israel launched 24 bombing runs in an hour.

South Beirut has been attacked repeatedly by Israeli warplanes since fighting began July 12. It is predominantly Shiite Muslim sector largely controlled by Hezbollah guerrillas, and Israel has not struck Beirut proper since the start of the war.

However, the strikes early Friday hit the affluent Christian locality of Jounieh, north of the capital, for the first time. The bombing against the picturesque coastal resort marked a sharp expansion of Israel’s attack on Lebanon, which now threatens Christian areas where.

Despite Hezbollah’s truce offer and continuing diplomatic efforts to broker a cease-fire, the Israeli army prepared to push up to Lebanon’s Litani River, about 20 miles north of the border as part of its campaign to force the guerrillas away from Israel and make room for a planned international force to patrol the area.

In the 24th day of Israel’s punishing onslaught both on the ground and from the air, Hezbollah has shown surprising strength and has found its support in Lebanon — and among the larger Arab world — vastly bolstered. With calls for a cease-fire growing more intense, it appeared likely that Hezbollah would emerge damaged but far from destroyed by the fighting.

Jordan’s King Abdullah II warned that the violence was causing a backlash against moderate Arab leaders and was strengthening the very radicals it was intended to destroy. “The Arab people see Hezbollah as a hero because it’s fighting Israel’s aggression,” he said.

Six Israeli brigades — or roughly 10,000 troops — are locked in battle with hundreds of guerrillas in south Lebanon.

An Associated Press count shows that at least 530 Lebanese have been killed, including 454 civilians confirmed dead by the Health Ministry, 26 Lebanese soldiers and at least 50 Hezbollah guerrillas. Lebanese Prime Minister Fuad Saniora said that 1 million people — or about a quarter of Lebanon’s population — has fled the fighting. Others estimate some 800,000 Lebanese have been made refugee.

Since the fighting started, 72 Israelis have been killed, 42 soldiers and 29 civilians. More than 300,000 Israelis have fled their homes in the north, Israeli officials said.

Defense Minister Amir Peretz told top army officers to begin preparing for a push to the Litani River, senior military officials said. Such a push would require further approval by Israel’s Security Cabinet and could lead to far more casualties.

The Israeli army said it has taken up positions in or near 11 towns and villages across south Lebanon as part of an effort to carve out a smaller 5-mile-deep Hezbollah-free zone.

In his televised speech broadcast Thursday night, Hezbollah’s Nasrallah for the first time offered to stop firing rockets into Israel if it stops its airstrikes. However, he also threatened to launch missiles into Tel Aviv if Israel hits Beirut.

Speaking directly to Israelis, Nasrallah added, “The only choice before you is to stop your aggression and turn to negotiations to end this folly.”

Israeli officials shrugged off the offer, saying Hezbollah was on the defensive and was looking for a breather.

At the United Nations, France has circulated a revised resolution calling for an immediate end to hostilities and spelling out the conditions for a permanent cease-fire.

British Prime Minister Tony Blair, who has postponed his summer vacation to work toward a U.N. resolution to the crisis, believes the coming days are crucial for securing agreement to end the fighting, his office said.

On Thursday night, Blair spoke to U.N. Secretary-General Kofi Annan, and early Friday to French President Jacques Chirac, a spokeswoman said.

Chirac called for an all-out effort toward a U.N.-backed cease-fire and a political agreement, which France wants ahead of any peacekeeping force

U.S. Secretary of State Condoleezza Rice predicted Thursday a U.N. Security Council resolution would be approved within days that would include a cease-fire and describe principles for a lasting peace. The plan could be embodied in two resolutions instead of one.

Israel, backed by the United States, has rejected calls for an immediate cease-fire, saying it first wants an international force or the Lebanese army to deploy in southern Lebanon to prevent future Hezbollah attacks.