Mauricio Alvarez, Víctor Jaimes, Juvencio Serpa and Elkin Menco, all leaders of the Unión Sindical Obrera (USO), Oil Workers Trade Union, in the city of Barrancabermeja, Norte del Santander Department, have received a death threat. Amnesty International is seriously concerned for their safety, and for that of other members of the USO.
