Indian rescue workers look at the mangled remains of vehicles buried under a partially collapsed overpass in Kolkata, India,Thursday, March 31, 2016. [Photo/IC]

Indian Prime Minister Narendra Modi, who is currently in the United States, has also expressed his shock over the tragic incident.

"Shocked & saddened by collapse of under construction flyover in Kolkata. Took stock of the situation & rescue operations," Modi tweeted. "My thoughts are with the families of those who lost their lives in Kolkata. May the injured recover at the earliest," he added.

Flyover collapses are not uncommon in India mainly due to the use of sub-standard materials and lack of adherence to safety standards.