The mishap occurred at about 3 pm this afternoon when four labourers engaged in the construction of AIIMS building here walked into the river, which is in spate due to incessant rains, for a bath, SP (rural) Mamata Vora said.
Three of them, all in their twenties, were swept away by the strong currents at Pashuklok barrage while the fourth somehow managed to swim to safety.
The lone survivor reported the matter to the police, she said.
Efforts are on to recover the bodies. Two of those drowned hail from Dhaulpur in Rajasthan and one from Agra in Uttar Pradesh, she said.