The fighting, between supporters and opponents of Syria's regime, has been concentrated in the Bab al-Tebbaneh and Jabal Mohsen districts of Tripoli, Lebanon's second city.
The reporter said tanks and jeeps entered the northern sector of Bab al-Tebbaneh but their progress was slowed by burning tyres and sniper fire, to which the troops responded.
Three soldiers were wounded in the fighting, according to the reporter and security officials.
A security official said the army had also deployed in Jabal Mohsen, which adjoins Bab al-Tebbaneh.
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They have fought frequently since the Syrian conflict erupted in March 2011.
Acting Prime Minister Najib Mikati said on Saturday that "security forces will take every step to put an end to the violence and chaos" in the city. "They will be strict and impartial."
But residents of Syria Street, which separates the two rival neighbourhoods, were sceptical.
"This is all a joke. It is the eighteenth time since May 2008 that they come to help. In fact, the army makes a small tour and then leaves. There is no solution," said Mustafa al-Hajj, a 69-year-old retiree.
"Each month it's the same thing."
Since the start of the latest violence, six residents of Jabal Mohsen, where the majority adhere to the same Alawite branch of Shiite Islam as Assad, have been killed, while eight residents of mainly-Sunni Bab al-Tebbaneh have died.
Tripoli is home to 200,000 people, 80 percent of whom are Sunni Muslims, 6-7 percent Alawites and the rest Christians.
Despite being a minority in the city, the Alawite residents of Jabal Mohsen have been able to hold their own in the clashes because their neighbourhood occupies higher ground and they are better organised than the Sunnis in Bab al-Tebbaneh.