World Bulletin / News Desk
Mohammed Ishtwei was abducted by militants shortly after leaving the city’s airport earlier in the day and was later found dead, the agency said, citing a local source.
His body was dumped outside the local morgue in the city.
No group has yet claimed responsibility for the attack.
The UN mission in Libya swiftly condemned the killing.
Ishtwei "was keen on stability of his city and his country, played an active role for the establishment of civil peace, and was seeking to strengthen harmony and reconciliation," it said in a statement on Twitter.
Libya has remained dogged by chaos and political uncertainty since 2011, when a bloody uprising led to the ouster and death of strongman Muammar Gaddafi after more than four decades in power.
The ensuing power vacuum swiftly led to the emergence of several competing seats of government -- including one in Tobruk and another in capital Tripoli -- and a plethora of heavily-armed militia groups.