The truck, which was not carrying goods and was on its way to Mirzapur from Aurai, fell into the river after breaking the railing of the bridge late last night, police said.
Bodies of driver Pappu (28) and labourers Gauri (30) and Rajpati (28), all locals, were recovered this morning, they said, adding an operation is on to find helper Vijay and Sunil.
Due to lack of visibility in the night, search operations could be started in the morning only and the three bodies and the truck have been fished out, police said.
Senior officials are at the spot and are overseeing search operations, they added.