KOLKATA: At least four people died and 18 others were injured on Tuesday when a fire engulfed a landmark building in the heart of the eastern Indian city of Kolkata.

"Four people jumped off the building when it caught fire and they were pronounced dead in hospital," local fire services minister Pratim Chatterjee said as firemen fought the blaze, four hours after it started.

Police joint commissioner Javed Shamim said 18 others were injured in the fire, which erupted on the second and third floors of the six-storey colonial-era structure in the city centre Park Street commercial district.

Some of the injured had either jumped off or fell while trying to escape the flames.

Groups of people including children clung on window ledges or perched on air conditioning units as cooking gas bottles exploded inside the complex, fuelling the flames which smothered Park Street with acrid smoke.

Residents using bamboo ladders and ropes evacuated around two dozen people from the building, which houses offices, upscale apartments, a popular restaurant and a clinic.

In February, nine people died in the southern city of Bangalore, some as they jumped from windows, when flames engulfed a tall building in the software capital.

Indian firefighters are badly equipped to fight major fires and often lack modern equipment, particularly long ladders capable of reaching trapped victims on high floors.

The design of the woollen uniforms worn by Mumbai firefighters was changed this month for the first time in nearly 100 years.