The victims, all residents of Durgasthan Mohalla area in Nalanda district, were taking dip before offering puja at Siddheshwarinath Temple near Makhdumpur when they slipped and drowned in the midstream, they said.
Rescue operations have been launched to trace them, they said.
Sub-divisional officer Ramniranjan Singh and Deputy Superintendent of police Bachha Singh were camping on the spot.