It was being built at a cost of Rs 1.5 crore, they added.
An under-construction small bridge collapsed in East Champaran district on Sunday in third such incident in Bihar in less than a week, officials said.
No casualty was reported in the incident that happened in Ghorasahan block in Motihari, they said.
The 16-metre-long bridge was being built over a canal by the state's Rural Works Department (RWD) to connect Amwa village to other areas of the block. It was being built at a cost of Rs 1.5 crore, they added.
"The exact cause of the incident is not yet known. It is a serious matter and a departmental inquiry has been ordered. Strict action will be taken against those found guilty," Additional Chief Secretary of RWD Dipak Kumar Singh told PTI.
"Senior officers of the district administration have reached the spot. A detailed report is awaited," he said.
District Magistrate Saurabh Jorwal said the exact cause of the incident was being ascertained.
"There are reports that a section of locals initially objected to the construction of certain pillars of the bridge. Police are also looking into this matter," he told PTI.
On Saturday, a small bridge collapsed in Siwan district. It was built over a canal, connecting the villages of Daraunda and Maharajganj blocks.
Prior to that, on Tuesday, a newly constructed bridge, about 180 metres long, had collapsed in the Araria district.
The state has been witness to several mishaps involving bridges, large and small, constructed over rivers and other water bodies. Though such incidents have not resulted in casualties, these have led to questions being raised on the quality of public works. PTI CORR PKD SOM
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