Security forces in the capital used tear gas and rubber bullets to disperse demonstrators on Saturday evening
Lebanon's Interior Minister Raya El-Hassan on Sunday ordered the country's security forces to open a "rapid and transparent" enquiry, after dozens of people in Beirut were wounded in clashes the night before.
Security forces in the capital used tear gas and rubber bullets to disperse demonstrators, who had gathered Saturday evening to demand an independent technocrat government ahead of talks due to begin Monday to appoint a new premier.
Hassan demanded the identification of those responsible for the most violent episode since the largely peaceful anti-government protests began on October 17.
She warned against "infiltrators" seeking to use protests to provoke "confrontations".
Amnesty International's Diala Haidar decried the "excessive use of force" in response to "overwhelmingly peaceful protest".
"The intention was clearly to prevent protesters gathering," she said, denouncing the presence of masked men in civilian clothes joining security forces in "violently attacking protesters".
On Sunday, French Foreign Minister Jean-Yves Le Drian said Lebanese leaders should push to resolve the crisis paralysing the country.
"Political authorities should get moving because the country is in a dramatic situation," he told French public radio.
Lebanon's government stepped down on October 29, but bitterly divided political parties have subsequently failed to agree on a new premier.
Saturday's clashes erupted at the entrance to the street leading to parliament, as security forces beat protesters who tried to breach metal police barricades.
Lebanese civil defence took 36 injured to hospital and treated 54 people at the scene, the organisation said on Twitter.