DUBAI, United Arab Emirates – A faulty elevator was behind the shutdown of the observation deck on the world’s tallest tower that effectively closed the half-mile-high Burj Khalifa to the public, witnesses and a Dubai rescue official said yesterday.

Visitors who were on the viewing floor at the time of Saturday’s incident told The Associated Press they heard a loud noise, then saw what looked like smoke but turned out to be dust seeping out of the crack in one of the elevator doors.

“It almost sounded like a small explosion. It was a really loud bang,” said Michael Timms, 31, an American telecommunications engineer who lives in Dubai and was visiting the tower with his cousin Michele Moscato.

About 45 minutes later, rescue crews arrived and pried open the elevator door, Timms said. The faulty elevator was caught between floors, so rescuers hoisted a ladder into the shaft to help those trapped inside get out.

Abu Naseer, a spokesman for Dubai’s civil defense department, confirmed the incident. He said the call for help came in around 6:20 pm Saturday evening.

Emergency crews used another elevator to reach the observation deck and were able to rescue all 15 people stuck inside the faulty elevator unharmed, he said.

The 2,717-foot (828-metre) building’s owner, Emaar Properties, has revealed few details about the incident since closing the observation deck indefinitely.

In a brief statement Monday, the company said the viewing platform was temporarily shut for “maintenance and upgrade” because of “unexpected high traffic.” It also hinted at electrical problems, saying “technical issues with the power supply are being worked on by the main and subcontractors.”

Emaar has made no mention of problems with the elevators. That angers some involved in the incident.

“What just kind of shocks me is that they were going to brush this under the rug to save face. If it broke, at least tell people it broke,” Timms said.

The company has not responded to specific questions about the incident or made anyone available to speak despite repeated requests by the AP.

Witnesses say the company provided little information to visitors stuck on the 124th floor observation deck as rescue crews worked. That lack of information caused panic among some visitors.

“I was really starting to get upset, getting really nervous,” said Moscato, 29, a nurse visiting from Columbia, South Carolina. “I started crying.”

She said she and Timms asked to use the stairs because they felt uncomfortable taking the elevator back down, but were told that was not allowed.

They, the people trapped in the elevator and an estimated 60 other visitors on the observation deck were eventually taken down in a freight elevator not normally used by the public, they said.

It remains unclear what exactly caused the elevator to fail.

Moscato said she spoke with a man, whose name she did not know, after he escaped from the elevator who said the lights went off and the elevator began to fall before the brakes kicked in. It was not possible to independently verify the account.

The US$1.5 billion Burj Khalifa opened with fireworks and other festivities in a widely televised celebration on January 4 after a series of delays.

It boasts more than 160 stories, but the exact number is not known. The tapering, silvery tower ranks not only as thejdhest building but also as the tallest freestanding structure in the world.

The observation deck, which is mostly enclosed but includes an outdoor terrace bordered by guard rails, is located about two-thirds of the way up on the 124th floor.