BEIRUT (Reuters) - Waves of Israeli air strikes destroyed three highway bridges north of Beirut on Friday, forcing U.N. relief agencies to cancel several convoys of aid for the 900,000 people displaced by the conflict.
The Israeli air force's bombing of bridges in the Christian heartlands north of the capital cut off the main coastal highway to Syria.
"It's really a major setback because we used this highway to move staff and supplies into the country," said Astrid van Genderen Stort of the U.N. refugee agency UNHCR. "If we don't have new material coming in, we will basically be paralysed."
Israeli raids have already wrecked the main Beirut-Damascus highway, although mountain roads still offer a perilous passage. Prime Minister Fouad Siniora warned on Thursday that the country only had enough fuel to last another week.
With no action to end the 24-day-old war emerging from the United Nations, the Israeli army prepared for a possible push to the Litani river, some 20 km (13 miles) north of the border, where 10,000 troops are already trying to dislodge Hizbollah.
Ferocious fighting continued in south Lebanon on Friday, the 24th day of a conflict sparked by a cross-border raid by Hizbollah in which two Israeli soldiers were captured.
Al Arabiya television said five Israeli soldiers were killed around the border village of Markaba. There was no immediate word from the Israeli army on the report.
"The thuds of explosions are continuous, warplanes are not leaving the skies. It is one of the worst days (of fighting)," a Lebanese security source said.
Israel renewed its bombing of Lebanese civil installations a day after Hizbollah attacks killed eight civilians and four soldiers, the heaviest one-day Israeli toll of the war.
At least 693 people in Lebanon and 68 Israelis have been killed in the conflict.
At least five people, including a Lebanese army soldier, were killed and 12 wounded in the bombing of the bridges, the Red Cross said. Another soldier was killed in overnight strikes on the Ouzai slum area near Beirut airport, the army said.
Bombs punched sections out of the bridges spewing rubble and twisted metal over passing cars.
Israeli air strikes also hit the Beirut-Damascus highway near the Syrian border, as well as other roads in the Bekaa Valley. Bombs shook Beirut's Hizbollah-dominated Shi'ite suburbs, where previous strikes had already levelled some areas.
Hizbollah's leader, Sayyed Hassan Nasrallah, offered on Thursday night to halt rocket attacks on Israel if the Jewish state ceased its bombardment of Lebanon, but he also threatened to lob missiles at Tel Aviv if Israel bombed central Beirut.
"If you strike Beirut, the Islamic Resistance will strike Tel Aviv and it is able to do so," Nasrallah said.
Israeli Defence Minister Amir Peretz ordered the army to prepare to push north to the Litani river, but Prime Minister Ehud Olmert's cabinet has yet to approve the offensive, which would go beyond a planned "security zone" in southern Lebanon.
Political sources said Olmert has so far objected to sending soldiers as far the Litani and is not convinced it would halt Hizbollah rocket fire into Israel, one of Israel's main aims.
"No decision has been made," Brigadier-General Ido Nehushtan told Reuters." An invasion up to the Litani would be Israel's deepest push into Lebanon since it surrounded Beirut in 1982.
Israel said its forces had occupied 20 villages up to seven km (four miles) from the border.
Nasrallah said Hizbollah would retain its capacity to rocket Israel even if Israeli forces penetrated as far as Beirut.
France and the United States were to hold more talks on a draft U.N. resolution aiming to end the fighting and strengthen U.N. peacekeepers until a more robust force can replace them.
Washington wants an international force in southern Lebanon immediately after a truce. But France, seen as a likely leader of the force, wants troops in only after a permanent ceasefire.
Israel has also launched an offensive in the Gaza Strip to recover another captured soldier and stop Palestinian rockets.
Israel killed three Palestinians in the southern Gaza Strip on Friday as it launched air strikes on militant targets that also wounded four people, witnesses and medics said.
At least 164 Palestinians, more than half of them civilians, have been killed since Israel's Gaza offensive began on June 28.
(Additional reporting by Jerusalem, United Nations bureaus)