The accident occurred late on Saturday in Raisen district, which lies adjacent to Bhopal where more than 3,500 people died in December 1984 after gas leaked from an Union Carbide pesticide plant into the city's atmosphere.

"People are complaining of severe breathing problems and many are complaining of itching in their eyes," Arun Kumar Bhatt, Raisen's district collector, told Reuters by phone on Sunday.

Officials said Saturday's leak was not even remotely as serious as the Bhopal tragedy nearly 22 years ago and that the state government reacted quickly by rushing people to hospitals.

Authorities in Raisen were trying to find out whether the leaked gas was ammonia or chlorine.

The victims would be discharged from hospitals in a few days, officials said, adding the government was trying to identify the plant responsible for the gas leak.

Bhopal has been witness to several toxic gas leaks in the past including in 2001 when three workers at an oil recycling plant died after inhaling fumes.