The chief minister also directed officials to ensure all possible help to the injured people.
Bodies of two labourers were on Saturday pulled out from the debris of a boulder that came down in a stone quarry in Sonbhadra, police said.
Three more labourers are feared trapped in the stone quarry in Billi Markundi mining area under Obra police station limits, they said. The boulder came down on Friday.
"The rescue operations, assisted by the NDRF (National Disaster Response Force), continued all through the night and the body of one labourer, Surendra (55), was found this morning," District Magistrate S Rajalingam said.
Superintendent of Police Ashish Srivastava said the body of the second labourer, Chhotelal (42), was also pulled out. It has been identified by his family members.
Three labourers are still feared trapped under the debris. Their family members are at the spot, he said.
The bodies of Surendra and Chhotelal have been sent for post-mortem, the police said.
On Friday, two labourers had sustained serious injuries after they came under the boulder. They are undergoing treatment at a hospital in Varanasi.
Uttar Pradesh Chief Minister Yogi Adityanath expressed grief over the loss of lives.
According to a statement issued by the UP government, instructions have been issued to provide financial assistance of Rs 2 lakh each to the family of the dead and Rs 50,000 each to the family of the injured.
The chief minister also directed officials to ensure all possible help to the injured persons and their proper treatment.