The child had gone to attend nature's call alongwith her mother last night in the Sujauli police station area when the leopard attacked her, they said.
Villagers rushed on hearing the cries of the mother forcing the leopard to flee but the girl had died by then, police said.
The locals raised slogans against the forest department and also protested in front of the police team which rushed to the village.
The family has been provided an immediate relief of Rs 10,000 and formalities are being completed for a compensation of Rs five lakhs to be granted, forest officials said.