Israel pounded Lebanon from the air on Friday (July 21) and one general said it might soon expand ground operations in its bloody assault on Hizbollah guerrillas. After 10 days of relentless bombardment which has destroyed much of Lebanon's infrastructure, Israel has been unable to stop Hizbollah firing rockets into the Jewish state, raising the possibility that it may have to push across the border in strength. The southern Lebanese port of Tyre has been the scene of some of the fiercest Israeli air strikes but Israeli jets also bombed Shi'ite districts in Beirut, the eastern Bekaa Valley and southern Lebanon around sunrise and struck a bridge on the main Beirut-Damascus highway four times. The Mdeirej bridge has already been bombed twice. In other raids, Israeli aircraft hit parked goods vans in the Bekaa, and a private power generator and garbage trucks in Beirut's Christian suburb of Baabda, near the presidential palace. There were no reports of casualties in the strikes. Lebanon's defence minister said on Friday (July 21) the army - which has not fought so far despite losing a score of soldiers in Israeli air strikes - would defend the country against invasion. Asked if the army would fight alongside Hizbollah against any Israeli ground incursion, Lebanese Defence Minister Elias al-Murr said, "If there is going to be a land invasion in Lebanon the role of the Lebanese army is very clear and it's defending the land and defending the country, protecting all the citizens and villages." "I can assure you that the Lebanese army will defend the land as soon and as well as we can. We will defend our land until the last soldier, we will pay the price for our land if we want a united army," Al Murr said. Israel warned Lebanese civilians to leave border villages on Friday and called up 3,000 reserves in a possible prelude to a ground offensive that would expand its 10-day-old campaign against Hizbollah guerrillas. Israeli planes dropped leaflets over south Lebanon warning civilians to flee for safety north of the Litani river, about 20 km (13 miles) from the frontier. There was no word on how many have already fled the bombing and fighting of the past few days. Air raids have wrecked many roads and bridges in the region. Elite Israeli troops have been launching small-scale raids in Lebanon to try to stop Hizbollah rocket attacks. But Israel has been wary of launching a full-scale invasion, only six years after it ended a costly 22-year occupation of the south. It first invaded Lebanon in 1978, pushing up to the Litani to try to drive Palestinian guerrillas from the border. The United Nations and many of its members have called for an immediate ceasefire in Lebanon, but the United States says this would not solve the conflict unless Hizbollah, which is backed by Syria and Iran, is prevented from attacking Israel. The relentless bombardment has killed 344 people and destroyed much of Lebanon's infrastructure. On Friday morning the extent of Israel's bombing was apparent as journalists picked through the ruins of a southern suburb of Beirut, led by a Hizbollah media officer. Rubble covered the streets and the innards of multi-storey buildings destroyed by the 9-days of bombings were exposed. The Hizbollah Al Manar television station was completely devastated. Israel began its assault after Hizbollah captured two soldiers and killed eight in a cross-border raid on July 12. It has also waged a military campaign in Gaza since June 28 to recover another soldier, seized by Palestinian militants. Hizbollah rocket attacks have killed 15 civilians in Israel, which has also lost 19 soldiers in the conflict.