Six labourers have been killed after a four-storey under-construction building collapsed on Thursday at a village here, officials said. One or more people are suspected to be trapped under the debris. The Gurgaon Fire Department control room received a call at 5.15 am from a local about the building collapse in Ullawas village. Three National Disaster Response Force teams, with about 35 personnel each, were deployed. The rescue operations are still underway.