NEW DELHI: A massive fire Tuesday gutted the National Museum of Natural History in India's capital, one of the country's top museums, an official said.

Firefighters took more than four hours to douse the blaze, which started on the top floor of the six-story museum, New Delhi fire official Harinder Singh said. Thirty-five fire engines were called. Singh said the entire building was gutted by the blaze.

Environment Minister Prakash Javadekar said the damage caused to the museum was being assessed. An investigation was ordered to determine the cause of the fire.

Five firefighters overcome by heavy smoke were taken to a hospital and released after being treated, Singh said. No other injuries were reported.

Rajesh Panwar, New Delhi's deputy chief fire officer, said the museum's fire safety equipment had not been functioning properly, making it more difficult for firefighters to finally bring the blaze under control.

Fires are common in buildings in India due to a lack of proper safety standards.

The state-run natural history museum features thousands of exhibits on plants, animals and mineral wealth in India and around the world.