The Burj Khalifa's owner said yesterday the observation deck of the world's tallest tower has been unexpectedly shut down, potentially disappointing thousands of tourists and marring the spire's image just a month after it opened.

The precise cause of the Dubai skyscraper's closure remained murky. In a brief statement responding to questions, building owner Emaar Properties blamed the closure on "unexpected high traffic", but then suggested that electrical problems were also at fault.

"Technical issues with the power supply are being worked on by the main and subcontractors and the public will be informed upon completion," the company said.

A spokeswoman for Emaar was unable to provide further details.

Thousands of visitors have taken the elevator ride of just over a minute to the observation deck since it opened to the public on January 5, though advance bookings have meant many tourists looking to visit have struggled to find tickets. Ticket holders affected by the shutdown are being offered the chance to rebook or receive refunds.

"All ticket holders who wish to rebook shall be given top priority," the company said, adding that it is "committed to the highest quality standards at Burj Khalifa".

Emaar did not say when the observation deck would reopen following last Sunday's closure. Ticket sales agents were accepting bookings starting on Valentine's Day this Sunday, though it has not been confirmed the building will reopen then.

Work is still ongoing on many of the building's other floors, including those that will house the first hotel designed by Giorgio Armani that is due to open in March.

It was unclear if the rest of the building was affected by the observation deck's shutdown. The first of some 12,000 residential tenants and office workers are supposed to move in this month.

Dubai opened the 2,717-foot (828 m) tower on Jan 4 in a blaze of fireworks that was televised around the world. The building had been known as the Burj Dubai during more than half a decade of construction, but the name was suddenly changed on opening night to honor the ruler of neighboring Abu Dhabi.

Dubai and Abu Dhabi are two of seven small sheikdoms that comprise the United Arab Emirates. Abu Dhabi hosts the federation's capital and holds most of the country's vast oil reserves. It has provided Dubai with $20 billion in emergency cash to help cover its debts.

The Burj Khalifa boasts more than 160 stories. The exact number is not known.

The observation deck is located on the 124th floor. Adult tickets bought in advance cost 100 dirhams ($27.25). Visitors wanting to enter immediately can jump to the front of the line by paying 400 dirhams ($109) apiece.

(Read by Renee Haines. Renee Haines is a multimedia journalist at the China Daily Web site.)

(Agencies)