According to MANA, the migrants found in the container appear to have been locked inside it for several days as it was transported to the coast at Khoms, where they were to attempt to cross the Mediterranean towards Europe, the Red Crescent said in a statement.
Fifty-six migrants were rescued from the container, some suffering from serious injuries and fractures, the statement said.
Another 14 migrant bodies were recovered from the sea near the coastal town of Zuwara, west of Tripoli, on Thursday, while some 124 migrants were rescued in the area, a local Red Crescent spokesman said.
Libya has become the main gateway for migrants trying to cross the Mediterranean to Europe. A record 181,000 migrants reached Italy along the route last year.
Within Libya, migrant smugglers operate with impunity, and migrants are subjected to a wide range of abuses, including rape, torture and forced labor.