The police evacuated the premises, which houses corporate offices, within 20 minutes.
The police, bomb squad and fire brigade teams inspected the area for two-and-a-half-hours but could not find anything objectionable. A dog squad was also pressed into service.
The employees of the call centre were moved to a safe spot.
Jagdish Prasad, SHO, DLF City Phase-2, told HT, "The unidentified caller said that he was calling from Mumbai and the bomb had been planted on three floors of the building. We are conducting investigations." A case has been registered.