Sources told Anadolu News Agency a quarrel broke out between a group of people trying to enter the headquarters of Haber-Is Labor Union and employees of the union.
Witnesses said the former financial secretary of the union and a group of some 25 non-workers arrived at union headquarters demanding that the former financial secretary be reinstated.
Shooting erupted when the group wasn't permitted to enter the building.
Ankara police detained five people, including the union's former financial secretary.
Notable deaths of 2014 [PHOTOS]