The GPO employees went on a strike following suicide by a co-worker on Friday.
Shahid Amin, 36, committed suicide due to workload. His fellows told media that he was transferred from his area, Badami Bagh, to another area and it increased his work and tension.
Amin, father of two, sent his children to school and ended his life in his house.
The GPO employees shouted slogans against the officer who transferred Amin and demanded facilities for the postmen.