The bodies of two minor Dalit girls, aged 13 and 16, were found in a field in Unnao district on Wednesday, police said.
Along with them was found a 17-year-old girl in a serious condition.
The three minor girls were found in the field in the evening by the villagers when they did not return after they left their house to bring fodder for the cattle, they said.
The villagers informed the police and rushed the girls to a hospital, where two of them were declared brought dead while one was taken to the Unnao hospital for treatment, they said.
The brother of the girls has claimed that his sisters were found with their hands and feet tied up.
Superintendent of Police Anand Kulkarni, who reached the spot, said that the two girls have died while the other one has been admitted to a hospital.
The bodies of the victims have been sent for postmortem and an investigation is underway, police said.
(With PTI inputs.)