The government said it has been unable to confirm Nuh's abduction from Tripoli airport, and no group has claimed responsibility for the act.
Militias have seized senior officials in Libya before in an effort to gain political leverage, like the hours-long kidnapping of Prime Minister Ali Zidan in October, the BBC said.
The kidnapping comes as a general strike in Tripoli was called as part of a protest over attempts by rival militias to exert control over the Libyan capital, a city official said.
Streets were largely deserted throughout Tripoli Sunday and roadblocks were found on streets manned by residents who wanted to prevent violence in their neighborhoods.
The head of Tripoli's city council said the general strike would last three days, and Zidan this weekend warned militia units battling on the outskirts of town to stay away.
Fighting began in a strategic Tripoli suburb Friday when fighters from a militia based in Misrata tried to enter the capital after a deadly protest outside the group's Tripoli offices, Voice of America said. At least 43 people were killed and fighting broke out when local militias blocked the approach of the Misrata cadre.
Friday's protest was led by residents of the city's Gharghour neighborhood who demanded the Misrata militia depart and allow Libyan national police to take over security in the area.