Protesters blocked roads across Lebanon on Monday over a deepening economic downturn that has led to a fuel crisis and severe power shortages.
The demonstrations came ahead of hikes in the price of fuel that the energy ministry said it would issue on Tuesday morning.
They also came as power cuts resulting from fuel shortages caused disruptions at a main Beirut hospital and at a security force headquarters in the capital, according to local media reports.
AFP correspondents said protesters blocked major roads and burned tires and garbage bins in Beirut, while the official National News Agency said roadways north and southeast of the capital were also blocked.
Protesters in the south Lebanon city of Nabatiyeh parked vehicles across a main artery to stop traffic, the NNA said.
The demonstrations took place after weekend scuffles between security forces and protesters that left nearly 20 people wounded in the northern city of Tripoli following a plunge in the value of the Lebanese pound.
Officially pegged to the dollar at 1,507 since 1997, the local currency now sells for a record low of more than 17,000 to the greenback on the black market.
On Monday, the central bank said it would provide fuel importers with dollars at a rate of 3,900 pounds to the greenback instead of the official rate, in compliance with a government decision issued last week.
The move effectively reduces subsidies on fuel as the central bank tries to shore up fast-diminishing foreign currency reserves.
The energy ministry said it would issue revised fuel prices on Tuesday based on the new exchange rate.
It said fuel tankers docked in Lebanese waters had started offloading fuel shipments that would boost supply in the coming days.
Lebanese have flocked to the gas pumps ahead of the price hikes, causing major congestion and massive queues.