A large crack in a pillar of the under construction bridge of the DelhiMetro in south Delhi could have caused its collapse early Sunday, killing fivepeople, say workers engaged at the accident site.

Five people, including a site engineer, were killed and 15 were injured in theaccident that took place at around 5 a.m. at Zamrudpur near East of Kailash,Delhi Metro Rail Corporation (DMRC) officials said.

Thirty workers of the contractor company Gammon India Ltd were present at theconstruction site when the bridge collapsed. Many strongly criticised Gammonand DMRC authorities for negligence saying they had complained several timesabout a faulty pillar.

Said Kishan, a construction worker present at the site: "There was a crackin the pillar and we had complained to authorities on various occasions. Theengineers came and suggested that support should be given to the pillar byinserting wires and putting boulders against the pillar."

Another worker said: "We told them that the crack was there and if notcorrected the pillar would be faulty and would cause the segment to comecrashing down - now it has."

Even residents of nearby residential colonies say they had seen a "visiblecrack".

A resident of Amar Colony, who identified himself as Dr. Tiwari, told IANS:"There must have been something faulty with the design. Because we hadseen a very visible crack in the pillar. We thought the stretch was stillunder-construction so we did not bother - but now this! Officials will have toprobe the negligence of the Metro and the contractor company."

Meanwhile, metro officials have held that the incident occurred because thelaunching girder of a segment of the bridge lost balance.

"The incident took place between pillars 66 and 67 when the pillar cap wasaffected. Ten segments were to be erected on the stretch of which five had beencompleted. When the sixth segment was being erected, the launching girdercollapsed due to disbalance causing a portion of the bridge to fall," DMRCspokesperson Anuj Dayal said.