DUBAI, United Arab Emirates The world's tallest skyscraper has unexpectedly closed to the public a month after its lavish opening, disappointing tourists headed for the observation deck and casting doubt over plans to welcome its first permanent occupants in the coming weeks. Electrical problems are at least partly to blame for the closure of the Burj Khalifa's viewing platform the only part of the half-mile high tower open yet. But a lack of information from the spire's owner left it unclear whether the rest of the largely empty building including dozens of elevators meant to whisk visitors to the tower's more than 160 floors was affected by the shutdown. The indefinite closure, which began Sunday, comes as Dubai struggles to revive its international image as a cutting-edge Arab metropolis amid nagging questions about its financial health. The Persian Gulf city-state had hoped the 2,717-foot (828-meter) Burj Khalifa would be a major tourist draw. Dubai has promoted itself by wowing visitors with over-the-top attractions such as the Burj, which juts like a silvery needle out of the desert and can be seen from miles around. In recent weeks, thousands of tourists have lined up for the chance to buy tickets for viewing times often days in advance that cost more than $27 apiece. Now many of those would-be visitors, such as Wayne Boyes, a tourist from near Manchester, England, must get back in line for refunds. "It's just very disappointing," said Boyes, 40, who showed up at the Burj's entrance Monday with a ticket for an afternoon time slot only to be told the viewing platform was closed. "The tower was one of my main reasons for coming here," he said. The precise cause of the $1.5 billion Dubai skyscraper's temporary shutdown remained unclear. 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, adding that it is "committed to the highest quality standards at Burj Khalifa."