Riot police and anti-government demonstrators have clashed for a second night in the Lebanese capital, Beirut, leaving dozens of people wounded.
Protesters threw bottles and fireworks at officers, who responded with tear gas and water cannon.
Meanwhile, the interior minister ordered an inquiry into a crackdown on Saturday that left dozens more wounded.
The unrest has been fuelled by anger at the ruling elite over the ailing economy and corruption.
The protests triggered the resignation of Prime Minister Saad al-Hariri in October, but talks about a new government are deadlocked.
On Monday morning, President Michel Aoun postponed until Thursday formal consultations with parliamentary blocs on who to choose as prime minister.
Mr Hariri, who had been expected to be nominated despite withdrawing his candidacy last month, requested the delay to allow “more consultation”, the presidency said.
Riot police forces were again deployed in large numbers on Sunday as thousands of protesters returned to the streets.
Lebanon’s Internal Security Forces said they fired tear gas after demonstrators pelted them with fireworks and stones.
The Lebanese Civil Defense said it had treated 72 people for injuries at the scene and taken 20 others to hospital.
The Lebanese Red Cross meanwhile said it had treated 37 on site and taken 15 people to hospital, according to AFP news agency.
Protester Omar Abyad, a 25-year-old unemployed nurse, told Reuters news agency: “They [security forces] attacked us in a barbaric way, as if we’re not protesting for their sake, their children.”
Interior Minister Raya al-Hassan urged the security forces to open a “rapid and transparent” investigation into Saturday’s violence but warned against “infiltrators” seeking to use protests to spark “confrontations”.
Diala Haidar, from the human rights group Amnesty International, said: “Security forces used excessive force to disperse an overwhelmingly peaceful protest. It only sends a clear message that security forces are above the law.”
The protests have been the largest seen in Lebanon in more than a decade. They have cut across sectarian lines – a rare phenomenon since the devastating 1975-1990 civil war ended – and involved people from all sectors of society.
Demonstrators are angry at their leaders’ failure to deal with a stagnant economy, rising prices, high unemployment, dire public services and corruption.
Their demands include an end to government corruption and the overhaul of the political system and the formation of an independent, non-sectarian cabinet.