The deadly stampede happened around 10:30 a.m. local time Friday on a footbridge at Prabhadevi train station, formerly known as Elphinstone station, Anil Saxena, spokesman for India's Ministry of Railways told local media.

Saxena said the crowd on the footbridge grew larger as people took cover during an unexpected rain shower. Once the rain stopped the crowd started moving and someone "must have slipped" leading to the initial blockage.

Television and social media footage from the scene shows heaving crowds of trapped commuters desperately trying to climb over railings and stairways to escape the crush, as lifeless bodies are pulled free.

In a message posted to his official social media account, Indian Prime Minister Narendra Modi expressed his "deepest condolences to all those who have lost their lives due to the stampede in Mumbai."

This is the second tragedy in less than four weeks to hit the western metropolis of more than 18 million. A building collapsed in the city following a week of heavy rains at the end of August, killing more than 33 people.

India's railways Minister Piyush Goyal is currently in Mumbai for a scheduled event. Writing on Twitter, he offered condolences to the families of those who had died in the stampede and promised a high level inquiry.

Goyal, who has spearheaded India's nascent drive to modernize its railway network and introduce high-speed bullet trains, came under fire on social media, however, as people took to Twitter to vent their anger at the allegedly dilapidated state of Mumbai's rail infrastructure.

The Indian rail network carries more than 23 million passengers daily, the equivalent to moving the entire population of Australia, and connects 8,000 stations across the subcontinent.

Speaking to CNN in January this year, Debolina Kundu, associate professor at the Indian National Institute of Urban Affairs, described the network's underlying infrastructure as stretched and overstressed. "Most of the bridges and culverts (tunnels) have outlived their lives," she said.

Prabhadevi Railway Station, which was first opened in the 1800s and has two platforms, is located in the heart of central Mumbai close to the exclusive Worli district, home to some of the city's most expensive real estate.