Protesters demanding the Lebanese government resign over its failure to remove uncollected rubbish from the streets clashed on Sunday with police in Beirut for a second day, leaving dozens injured.
The demonstration in downtown Beirut turned violent when around 200 youths entered Riad al-Solh Square, hurling projectiles at security forces who responded by firing tear gas and water cannon.
Officials said 43 protesters were hospitalised while 30 members of the security forces were also injured.
It came hours after Prime Minister Tammam Salam pleaded for calm and said he was ready to meet members of the "You Stink" protest movement which blames political divisions for the crisis.
Anger about rubbish overflowing in the streets since Lebanon's largest landfill was closed on July 19 boiled over on Saturday when thousands rallied outside the prime minister's office in central Beirut.
But Saturday's peaceful demonstration turned violent as protesters pelted police with water bottles and firecrackers, and police retaliated with tear gas, water cannon and apparent gunfire. Sixteen people were injured.
In response, Salam pledged to hold accountable those responsible for using "excessive force against civil society and against the people", but violence erupted again on Sunday.
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 erect their own barricades.
Police retaliated with water cannon and tear gas.
A Red Cross official said 43 protesters were injured and taken to hospital, while another 200 people were treated on the spot.
A security official said 30 members of the Internal Security Forces were also injured, one seriously.
Shots also rang out near the prime minister's office, where thousands of people had also clashed the day before. It was not immediately clear if the shots were live fire, blanks, or rubber bullets.
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 message that read "Some trash should not be recycled" and below it the pictures of more than a dozen politician.
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- 'Political trash' -
Videos posted online by protesters showed members of the security forces firing into the air and beating the demonstrators.
The "You Stink" movement insisted they were opposed to violence and distanced themselves from those attacking security forces.
"They're not among us... they're a very small group of troublemakers," said Joey Ayoub, who sits on You Stink's organising committee.
He said his movement had moved the protest from Riad al-Solh Square, where the clashes occurred, to nearby Martyrs Square "to show that we are not involved in this violence".
Ayoub said the movement's most pressing demand was for security forces to be held accountable for Saturday's use of force.
An online statement also called for the prosecution of Interior Minister Nuhad Mashnuq.
Furious demonstrators have posted videos and photos on social media of security forces firing into the air and beating back protesters during Saturday's unrest.
The prime minister tried to ease tensions, saying he was ready to meet with a You Stink delegation, saying "I am ready to listen to you and sit with you".
"We cannot allow yesterday's events to pass without accountability and follow-up," said Salam.
He called on Lebanon's cabinet to meet this week to find a solution to the crisis, railing against political divisions that have paralysed the country's institutions
Profound political rifts have kept Lebanon without a head of state since May 2014, leaving a caretaker cabinet -- also deeply divided -- in charge.
Salam said the country's trash crisis was the "straw that broke the camel's back."
"But the story is bigger than this straw. This is about the political trash in this country," he said.
Furious demonstrators have posted videos and photos on social media of security forces firing into the air and beating back protesters during the weekend's unrest.