Lebanese Prime Minister Saad al-Hariri has said he would submit his resignation, declaring he had hit a "dead end" in trying to resolve a crisis unleashed by huge protests against the country's ruling elite.
The Sunni politician addressed the nation in a televised address after a mob loyal to Shia Muslim groups Hezbollah and Amal attacked and destroyed a protest camp set up by anti-government demonstrators in Beirut.
Lebanon has been paralysed by the unprecedented wave of protests against the rampant corruption of the political class that has collectively led Lebanon into the worst economic crisis since the 1975-90 civil war.
"For 13 days the Lebanese people have waited for a decision for a political solution that stops the deterioration (of the economy). And I have tried, during this period, to find a way out, through which to listen to the voice of the people," Mr Hariri said in his speech.
"It is time for us to have a big shock to face the crisis. I am going to the Baabda (presidential) palace to present the resignation of the government. To all partners in political life, our responsibility today is how we protect Lebanon and revive its economy."
In central Beirut, black-clad men wielding sticks and pipes wrecked the protest camp that has been the focal point of countrywide rallies against the long entrenched elite.
The turmoil has worsened Lebanon's acute economic crisis,with financial strains leading to a scarcity of hard currency and a weakening of the pegged Lebanese pound. Lebanese government bonds tumbled on the turmoil.
The show of force in Beirut came after Hezbollah leader Sayyed Hassan Nasrallah said last week roads closed by protesters should be reopened and suggested the demonstrators were financed by its foreign enemies and implementing their agenda.
It is the most serious strife on the streets of Beirut since 2008, when Hezbollah fighters seized control of the capital in a brief eruption of armed conflict with Lebanese adversaries loyal to Mr Hariri.
Smoke rose as some of the protester tents were set ablaze by Hezbollah and Amal supporters, who earlier fanned out in the downtown area of the capital shouting "Shia, Shia" in reference to themselves and cursing anti-government demonstrators.
"With our blood and lives we offer ourselves as a sacrifice for you Nabih," they chanted in reference to Parliament Speaker Nabih Berri, head of the Amal Movement. "We heed your call, we heed your call, Nasrallah," they chanted.
Security forces did not initially intervene to stop the assault, in which protesters were hit with sticks and were seen appealing for help as they ran, witnesses said. Tear gas was eventually fired to disperse the crowds.
Nationwide protests since 17 Octobe have paralysed Lebanon at a time of worsening financial crisis - banks were closed for a 10th day today, along with schools and businesses.
Mr Hariri's resignation would defy the powerful Hezbollah - Nasrallah has twice said that he was against such a step, citing the risk of a dangerous void.
According to the constitution, Mr Hariri's cabinet would stay on in a caretaker capacity until a new government is formed.
Mr Hariri last week sought to defuse popular discontent through a batch of reform measures agreed with other groups in his coalition government, including Hezbollah, to - among other things - tackle corruption and long-delayed economic reforms.
