TRIPOLI: Libyan authorities have uncovered a mass grave containing the bodies of 21 migrants from sub-Saharan Africa, local media reported Thursday. News outlets cited government sources as saying a Libyan national has been arrested on suspicion of killing the migrants and holding others captive on a farm in the northeastern town of Ajdabiya. Libya is a key transit country for thousands of migrants attempting to reach Europe each year, with deaths among migrants frequently reported. The Internal Security Agency for Libya’s east said it had “discovered a mass grave containing the bodies of 21 individuals of various African nationalities”, according to television channel al-Masar.