A slab portion of the flyover being constructed by the National Highway Authority of India (NHAI) collapsed at the Phutaiyya Chauraha, an official said.

"The incident took place in the morning in which a labourer on night-shift duty was injured. He was immediately admitted to the district hospital," Basti District Magistrate Raj Shekhar told IANS.

The traffic in the area, which was suspended following the crash, has been allowed with precautions like barrier and barricades.

Chief Minister Yogi Adityanath has directed the district authorities to ensure that the injured get prompt and adequate treatment, a government spokesman said.

Project Director of the NHAI for northern division has been asked to initiate a probe into the incident.

The crash comes two months after a similar portion of another under-construction flyover in Varanasi collapsed leaving 18 dead and many injured.

That flyover in Prime Minister Narendra Modi's parliamentary constituency was being built by the Uttar Pradesh Rajkiya Nirmaan Nigam (UPRNN), a state government agency.