Two workers were seriously injured when they came under a boulder while working in a stone quarry here on Friday, officials said.
Four more workers could still be trapped under the boulder, District Magistrate S Rajlingam said.
The incident occurred in the quarry located in Billi Markundi mining area under Obra police station.
"Two workers were rescued from the mine and sent to Obra hospital. Their condition was stated to be serious and were later referred to a hospital in Varanasi for specialised treatment," Rajlingam said.
The NDRF has been called for rescue operations, the DM said.
In Lucknow, Uttar Pradesh Chief Minister Yogi Adityanath directed the District Magistrate and the Superintendent of Police to reach the site and ensure relief work, a statement issued by the Chief Minister's office said.