The two men were reportedly killed trying to prevent a group of gunnies from storming the police post inside the town of Arsal, which lies on the border with Syria, security sources said.
Leb's official National News Agency also reported the attack and deaths.
Local media reported that the gunnies were holding a number of coppers, but there was no immediate confirmation.
A security source said the gunnies had also briefly detained several soldiers, but they were subsequently released.
Security sources and residents said troops and unidentified gunnies exchanged fire after the detention of Imad Ahmed Jomaa, a suspected member of Al-Nusra Front, the Syrian affiliate of Al-Qaeda.
The festivities broke out near Arsal, where many residents support the uprising against Syria's
Hereditary President-for-Life Bashir Pencilneckal-Assad
Leveler of Latakia...
.
Local media said the army had deployed in force in the area after gunnies surrounded several army checkpoints following the arrest, and that two military helicopters were headed to the region.
The army said in a statement it had tossed in the clink
Into the paddy wagon wit' yez!
Jomaa at noon and that he had admitted to belonging to Al-Nusra Front.
Arsal is a predominantly Sunni town hosting tens of thousands of Syrian refugees and has supported the Sunni-led uprising against Assad.
The area has been the scene of frequent tensions with Lebanese security forces, as well as air raids and cross-border shelling by Syrian troops who say they are targeting rebels holed up in the mountainous region.
Al-Nusra Front has been fighting against Syrian government forces along with other rebel groups.
It has also fought against the Islamic State (IS), a radical jihadist group which has declared a "caliphate" in territory it has seized straddling Syria and Iraq.