Thousands of Lebanese supporters of the Hezbollah-led opposition parties have taken to the streets of Beirut.
The protesters have set cars and tyres alight, blocking the major access routes into the capital.
Their aim is to enforce a general strike to try to topple the pro-Western government.
Smoke from burning tyres billowed out across the Lebanese capital from the early hours of the morning.
The strike made life difficult for ordinary people. Many shops and schools were forced to close.
Soldiers intervened to stop stone-throwing between opposition protesters and pro-government supporters.
But witnesses said security forces had taken little action to keep roads open.
Protesters succeeded in closing down most main roads in Beirut, as well as motorways to the north and south.