Supporters of the Hezbollah-led opposition blocked roads in the capital on Wednesday to enforce a strike called by labor unions protesting the government's economic policies and demanding pay raises.

The strike quickly escalated into street confrontations between supporters of the rival camps. About a dozen people were injured, mostly by stones, but no deaths were reported.

On Thursday, the violence spread outside the capital. Sunnis and Shiites exchanged gunfire in the village of Saadnayel in the eastern Bekaa Valley. Four people were injured, said security officials, speaking on condition of anonymity in line with military regulations.

The area is on a major crossroads linking the Shiite areas of Baalbek, a Hezbollah stronghold, with central Lebanon and Beirut.

Nasrallah claimed Hezbollah's secure network of primitive private land lines helped the guerrillas fight Israel's high-tech army in the 2006 summer war.

He said the telecommunications network was "the most important part of the weapons of the resistance" and added Hezbollah had a duty to defend those weapons.

Hezbollah supporters kept the road to the country's only airport blocked, effectively closing the airport for a second day.

The clashes have brought back memories of the devastating 1975-1990 civil war that has left lasting scars on Lebanon.

Beirut residents are now seeing fresh demarcation lines, burning tires and roadblocks.

Copyright 2008 The Associated Press.