DUBAI (REUTERS/AFP) - Hundreds of people in Dubai were evacuated from one of the world's tallest residential buildings on Saturday when fire swept through The Torch, a 79-storey skyscraper.

A witness said flames shot out from two sides of the building as glass and metal rained down from near the summit of the structure, which stands at more than 330m tall.

Medics said there were no casualties. At least a dozen fire trucks were able to extinguish the blaze several hours after the fire alarm went off around 2am local time (6 am on Saturday, Singapore time).

However, some residents said they had been told by staff that the building's fire alarms did not immediately sound and that the reception at The Torch was alerted to the fire by staff in an adjacent building.

"They (the Torch receptionists) got a call from Princess Tower telling them the building was on fire. The alarms were not operating automatically," Archibald Jurdi, who lives on the 76th floor, told Reuters.

Reuters could not independently verify the status of the fire alarms. The building manager could not be reached for comment.

Residents said the fire had been fanned by high winds, dislodging chunks of metal and raining glass down on the area below the building, including onto a nearby road more than 100m away.

Traffic in the area was diverted and residents of two other nearby buildings in the marina district, home to thousands of expatriate professionals, were also evacuated, the witness said.

Many of those standing outside the building were dressed in pyjamas, with others in formal evening wear as they returned from the city's many bars and restaurants on a weekend.

One woman, who did not give her name, stood on the street crying, saying she had rushed back fearing for her belongings after a friend contacted her about the fire. Her fear turned to relief when she saw the lower floors where she lived were not affected.

Residents of neighbouring towers returned to their homes at around 4.30am, but residents of The Torch were told they would not be allowed back into the building until the fire officials gave approval later on Saturday. Residents of upper floors that were most affected were told it would be days before they could return.

Dubai's civil defence officials did not immediately respond to requests for comment, and the cause of the fire remained unclear.

Dubai is one of seven emirates that make up the United Arab Emirates (UAE), a Gulf Arab trade and investment hub. It is known for its skyline of hugely varied skyscrapers and has seen fires at towers in the past.

In 2012, a huge blaze gutted the 34-Tamweel tower in the nearby Jumeirah Lake Towers district. It was later revealed to have been caused by a cigarette butt thrown into a bin.