The mishap took place as the under-construction chimney of a brick kiln unit in Chaita Deviraji tola collapsed trapping four labourers under its rubble, the sources said.
The injured labourers were taken to a private clinic where three of them died during treatment, while another labourer was recuperating, they said.
The bodies have been sent for post-mortem, they said.
An FIR has been lodged against the brick kiln unit owner Arun Kumar Singh, the sources added.