Officials said the incident occurred around 4.30 a.m. when a large section of the ageing bridge caved in, reportedly due to soil erosion around its foundation. The bridge, constructed in 1963, was under maintenance at the time.

The collapse has severely disrupted connectivity across upper Assam, with long queues of vehicles stranded on both sides of the highway. Authorities have diverted traffic through alternative routes where feasible, but movement in the region remains affected.

A truck reportedly plunged into the river while attempting to cross the weakened stretch of the bridge. There were no immediate reports of casualties.

The bridge had been under scrutiny for its deteriorating condition. Earlier this year, a portion of its central span had been washed away, leading to repair work and restrictions on vehicular movement.

Emergency response teams and officials from the local administration have reached the site to assess the extent of the damage and initiate restoration efforts. Commuters have been advised to avoid the route until further notice.