Mumbai | A major blaze broke out at the Enforcement Directorate's office building in south Mumbai in the early hours of Sunday, and the firefighting operations have continued for more than six hours, officials said.

There were no reports of casualties in the fire that broke out at the Kaiser-I-Hind building in the Ballard Estate area, they said.

Officials said the blaze, which started on the fourth floor of the five-storey building housing the ED office around 2.31 am, has continued to rage despite efforts.

Firefighters are struggling to bring the blaze under control, a fire brigade official said.

Mumbai Fire Bridge upgraded the fire to Level III at around 4.17 am, which is generally considered a major fire.

At least eight fire engines, six jetties, water tankers and other equipment have been deployed to the spot.

The official said several documents and equipment inside the office are feared to have been damaged.

He said the exact cause of the fire is yet to be ascertained.