NEW DELHI — A portion of a bridge in the Indian city of Kolkata collapsed on Tuesday, sending vehicles nose-diving into the wreckage, killing at least one person and possibly trapping several others, government officials said.Witnesses said the bridge collapsed during late afternoon traffic in the upscale neighborhood of Alipore, in southern Kolkata, a dense metropolitan area with over 14 million residents.At least 19 people were rushed to a local hospital with injuries.Several men working in an office near the bridge told ANI, an Indian news channel, that they heard a loud sound before the power went out. When they rushed outside, cars and motorbikes were tangled in a broken slab of the bridge. One of the men said bystanders were trying to pull injured people from the debris.Mamata Banerjee, the chief minister for the state of West Bengal, which includes Kolkata, formerly known as Calcutta, told the news media that five to eight workers in a small office under the bridge were thought to be trapped.With the cause of the collapse unknown, the governor of West Bengal, Keshari Nath Tripathi, called for an investigation, telling reporters that “the bridge deserved better maintenance” and that there had been previous complaints about the soundness of the concrete structure.After the accident, police, fire and disaster management officials were dispatched to the 40-year-old bridge, where panicked relatives of missing people congregated and rain lashed down.“Our main focus right now is rescue and relief operations,” Ms. Banerjee said, adding that the injured would receive 50,000 rupees, or about $700, from the government. The government often provides compensation after accidents in India, where many people still survive on a few dollars a day.The Indian news media identified the person who died as Soumen Bag, who was in his 20s.Shoddy construction projects and reports of collapsing bridges and flyovers are common in India. In 2016, part of an unfinished flyover, a 330-foot slab of steel and concrete, crashed down into midday traffic in Kolkata, killing at least 26 people and leading to protests in the streets from residents living nearby.Prime Minister Narendra Modi called Tuesday’s bridge collapse “deeply unfortunate.” “I pray that those who are injured recover at the earliest,” he wrote on Twitter.