Four labourers, who were working on the construction of a new bridge, were killed when a 10-feet high mound of soil collapsed and buried them in Bihar's Madhubani district, police sources said on Monday. Two labourers were seriously injured in the incident.

All four victims belonged to a Dalit community. "The four labourers died on  Sunday after a high mound of soil collapsed and fell on top of them. They were residents of Bhagwatipur village in the district," police sources said.

According to officials of the district administration, the labourers had been employed by IRCON, which was constructing a new bridge in place of an old bridge.

"A high mound of soil suddenly collapsed and buried four of them alive, when they were busy breaking down the old bridge," official sources said.