The Islamic State aired a video on Saturday of a captive soldier pleading to his family to pressure the state to release Islamist inmates in Roumieh Prison.
Ali al-Hajj Hassan pleaded for his family to take action “otherwise the gunmen will execute the captives.”
They were given three days to comply with the demand.
“We can no longer support the situation … Please liberate us before they kill us,” al-Hajj Hassan said in the video.
Al-Hajj Hassan had not appeared in previously released videos of the captives because he was not present at the shooting location.
The families of the remaining captives staged demonstrations on Sunday, blocking the main highway in the Bekaa's Labweh region to protest their ongoing kidnapping.
A number of soldiers and security forces members were kidnapped after clashes between the army and Islamists in the northeastern town of Arsal in early August.
The clashes erupted on August 2 in light of the arrest of a prominent al-Nusra Front member.
The fighting ended on August 7 with the militants withdrawing from the region, but kidnapping a number of soldiers and security forces members.
A few of them have since been released, including five on Saturday.