The south-western belt of Mizoram was cut off from rest of the state after part of a Bailey bridge over the Phairuang river collapsed on National Highway 302 which links south Mizoram’s Lunglei town with Tlabung near the Bangladesh border, a senior official said on Sunday.

The Bailey bridge, nearly 39.5km from Lunglei, is the lifeline of the south-western belt of the state, including the border town of Tlabung.

State PWD engineer-in-chief K. Lalsawmvela told this correspondent that at least 12 vehicles, including three heavy trucks, and many commuters were stranded since Tuesday when the bridge partially collapsed because of cracks in the steel cross beam.

He said repairs were in progress and the bridge was opened for vehicles around 10pm on Sunday.

Lalsawmvela said the cable stayed steel suspension bridge over the Phairuang was constructed by the Border Roads Organisation (BRO) 39 years back and had become fragile and weak.

“It is a wooden deck bridge and is too old to be used frequently,” he said.

The official added that chief minister Zoramthanga had appealed to the Union ministry of road transport and highways (MoRTH) and met the minister concerned on three occasions for allocation and sanctioning funds for the construction of a new bridge as a standalone project.

The state government has also submitted detailed project reports (DPR) to the ministry.

Lalsawmvela said: “The bridge is prone to collapse if sanction is not obtained quickly. A new concrete bridge must be constructed on time.”

According to sources, there are more than 50 bridges across the state which are under the PWD and some of them are in vulnerable condition.

So far, at least four persons had died due to collapse of other bridges on six occasions since 2014.