Lebanese troops moved in to diffuse protests in the coastal city of Sidon after demonstrators gathered at the end of Friday prayers.
Gunfire was reported in the southern city of Sidon, but few details regarding casualties were available.
The military moved to break up the demonstration after protesters tried to reach the mosque complex where fugitive cleric Ahmad al-Assir used to give his sermons.
The compound has been under army control since Monday, after two days of fighting between troops and Assir's followers that left dozens of people dead, 18 of them soldiers.
Al Jazeera's Nour Samaha, reporting from Beirut, said the situation in Sidon had been calmed when the army dispersed protesters by firing into the air, but Tripoli remained tense.
Demonstrators have come out in favour of the cleric, but also because of a growing feeling that, as Sunnis, they feel targeted by the arm, who they believe to be working on behalf of Hezbollah.
Our correspondent said news channel Al Jadeed was reporting that protesters in Tripoli had been seen taking down pictures of former Prime Minister Saad al-Hariri and replacing them with pictures of Assir and black Salafist flags were seen during the protests.
Spordic gunfire in Tripoli has been reported, but is not thought to have been between rival factions or parties.
Further protests had been called for in Tripoli, the northern district of Akkar, Tariq Jdideh in Beirut, and Saadnayel in the Bekaa Valley, but so far both Beirut and Saadnayel seem to have avoided being the scenes of any confrontation.