BEIRUT - At least 20 people were injured Sunday in Beirut during a second day of clashes between police and protesters angry about the Lebanese government's failure to remove rubbish from streets, medics said.

Around 200 youths, some wearing scarves or masks to cover their faces, threw stones and bottles filled with sand at police and tried to pull down security barricades, an AFP correspondent said. They also set on fire a motorcycle and tried to set up their own barricades using tables and wood.

Police retaliated with water cannon and tear gas. Some protesters suffered smoke inhalation and were taken away by ambulances for treatment.

A Lebanese Red Cross official said 20 protesters were injured, including 13 who were hospitalised. Some shots also rang out in central Beirut, near the prime minister's office, where thousands of people had rallied peacefully during the day before the violence broke out.

The "You Stink" movement that organised the rally insisted they were opposed to violence and distanced themselves from those attacking security forces. Protesters chanted "Down with the regime" and "Freedom", slogans borrowed from the Arab Spring uprisings that toppled several governments in the region.

One demonstrator held up a placard with a bold red message that said "Some trash should not be recycled" and below it the pictures of more than a dozen of top politicians.

On Saturday, at least 16 been were injured during clashes with police, according to a Red Cross official, while the Internal Security Forces said more than 35 of its members were also hurt.

Prime Minister Tammam Salam held a news conference to plead for calm on Sunday, and pledged to hold accountable those responsible for using "excessive force against civil society and against the people".

Lebanon's largest landfill was shut on July 17, leaving piles of rubbish to rot uncollected in Beirut and across the country, sparking anger among civilians who accuse authorities of negligence.