At least 15 Lebanese soldiers are now known to have died in clashes between government troops and followers of a Sunni sheikh, who is opposed to the Shia movement Hezbollah and its involvement in the war in Syria.
The clashes which broke out on Sunday between the army and supporters of Ahmad al-Assir continued overnight in Sidon, reported Al Jazeera's Nour Samaha on Monday.
The fighting raged around Abra and the Ain el Helweh Palestinian refugee camp near Sidon, she said.
Members of the Jund al Sham and Fatah al Islam armed groups have joined the battle, she added, reporting from a village several kilometres away from Sidon.
She said clashes had "intensified in both areas mentioned above, with heavy weaponry being used".