Sunday's confrontation escalated near parliament a day after more than 370 people were wounded in the biggest casualty toll since the protests began.
Mass protests engulfed Lebanon last October amid a crippling economic crisis.
For the second night in a row, dozens of people started lobbing stones at police behind a metal barricade blocking a road to parliament, crying "revolution, revolution".
Human Rights Watch said riot police had fired tear gas canisters at the heads of some protesters and rubber bullets at their eyes.
The Red Cross said more than 145 people were injured, including 45 who needed treatment in hospital.
The area outside Parliament was packed with journalists, many of them correspondents for global news agencies.
Earlier Sunday, security forces reinforced the metal barriers surrounding the Parliament building in central Beirut, after the worst night of violence since protests erupted several months ago. Those clashes left at least 377 people injured, the Red Cross and the Lebanese Civil Defense said.
In a statement released overnight, Lebanon's State Security department said the USA citizen was at the scene of the protest near the parliament building, a location from which someone was broadcasting live to the Israeli paper.
"Violence only breeds violence", she said.
"Injured internal security officers were attacked by a number of rioters at Alwardiyah Hospital and American University of Beirut Medical Center", the statement says. "It's clear that the more they (security forces) step up their violence, the more people's strength and determination grow".
A Reuters witness saw police fire rubber bullets. But the army pulled out minutes later, and the clashes resumed with security forces barricaded behind the barriers.
"Our government resigned in order to transition to a new government dealing with popular changes but obstruction has continued for 90 days and the country is moving toward the unknown", Hariri said in a tweet.
"Another day without a government, another night of violence and clashes", United Nations envoy to Lebanon Jan Kubis said on Twitter.
In a show of defiance, demonstrators who said they took part in the weekend protests responded online using the Arabic hashtag "The Infiltrator Is Me", disclosing their full personal details.
Political factions agreed on December 19 to appoint former education minister Hassan Diab as the new premier but have since squabbled over proposed ministers.
Protesters have been demanding a technocrat government of independent ministers capable of implementing reforms and fighting against corruption.
The World Bank has warned that the poverty rate in Lebanon could rise from a third to a half if the political crisis is not remedied fast.