Lebanese troops and gunmen have exchanged fire in Beirut's southern suburbs today.
Five people have been wounded, deepening a political crisis following the assassination of a senior intelligence official, security and medical sources said.
Four people were also killed, including a nine-year-old girl, while 12 people have been wounded in clashes between gunmen in the northern city of Tripoli, the sources said.
Anti-government protesters continue to block main roads in the Lebanese capital as government soldiers have been deployed in the streets.
The violence heightened fears that the civil war in neighbouring Syria could be spreading into Lebanon.
Tensions have been high in Lebanon since Friday, when Brigadier General Wissam al-Hassan, an intelligence chief opposed to the Syrian leadership, was assassinated in a car bombing.
Many politicians have accused Syria of being behind the killing and angry protesters tried to storm the government palace after Mr Hassan's funeral yesterday.
Opposition leaders and their supporters want Prime Minister Najib Mikati to resign, saying he is too close to Syrian President Bashar al-Assad and his Lebanese militant ally Hezbollah, which is part of Mr Mikati's government.
The clashes in Beirut this morning took place on the edge of Tariq al-Jadida, a Sunni Muslim district that neighbours Shia Muslim suburbs in the south of the capital.
Residents had earlier reported heavy overnight gunfire around Tariq al-Jadida between gunmen armed with rifles and rocket-propelled grenades.