Lebanon needs to quickly form a new government to stop a cycle of collapse and worsening economic and security conditions, caretaker prime minister Saad al-Hariri tweeted on Monday.
Politicians have failed to agree on a government or an economic rescue plan since protests pushed Hariri to quit as prime minister in October.
Beirut has been rocked in recent days by some of the worst violence since the unrest began, with 370 injured in clashes between protesters and security forces on Saturday.
President Michel Aoun met security chiefs on Monday to work out a plan for deterring violent groups that "security services have detailed information on" while protecting property and peaceful protesters, sources at the meeting said.
Lebanon's unrest is fuelled in part by deep financial strains that have sunk the currency, pushed up prices and driven banks to impose capital controls.
"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.
Last month little-known former minister Hassan Diab was designated prime minister with the backing of Islamist movement Hezbollah and its allies, but a deal on a cabinet has yet to be announced.
"The continuation of the caretaker government is not the solution so let's stop wasting time and have the government bear the responsibility," Hariri said.
