Politicians have failed to agree on a government or an economic rescue plan since the protests pushed Saad al-Hariri to quit as prime minister in October.
"We have gone from being a country we used to call the Switzerland of the east to a country ranked at the bottom in everything," said housewife Rezzan Barraj, 47, at Sunday night's protest.
"It's clear that the more they (security forces) step up their violence, the more people's strength and determination grow."
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A Reuters witness saw police fire rubber bullets. The Lebanese Red Cross said it treated 52 people and took 38 to hospital.
Hundreds of people yelled "revolution" in the commercial district of the capital. Protesters pelted riot police with stones and fireworks.
Some tried to climb over barbed wire and fencing to storm a heavily barricaded part of central Beirut that includes parliament. One man jabbed police with a pole across the barriers as the violence escalated.
Protests Downtown Beirut: 12 teams from the #Lebanese_Red_Cross are intervening. 30 people have been transported, until now, to nearby hospitals and 40 have been treated at the scene. Extra teams are on standby and ready to intervene. pic.twitter.com/4eo0VQgb2B