London Olympics organizers are coming under fire over bungled security staffing and other issues that have prompted British media and opposition lawmakers to declare the Games a "fiasco."

LONDON — “Ten days to the Games — what could go wrong?” a sarcastic headline in Britain’s Guardian newspaper asked Tuesday. The answer, as this Olympic host nation has discovered, is: Quite a lot.

Even as athletes begin arriving in London for the 2012 Games, Olympic organizers are coming under fire over bungled security staffing and other issues that have prompted British media and opposition lawmakers to already declare the event a “fiasco.”

On Tuesday, organizers said they would withdraw about 500,000 tickets for soccer matches and reduce stadium sizes because of scant demand in farther-flung host cities in Britain, including Glasgow and Cardiff.

A day earlier, U.S. and other athletes were hauled around for hours on at least two buses that lost their way en route to the Olympic Village in East London.

That joy ride paled in comparison with the security blunders casting a shadow ahead of the Games. The private contractor hired to provide guards — British giant G4S — conceded last week it was at least 3,500 personnel short, sending the military scrambling to make up the gap.

On Tuesday, furious lawmakers summoned the company’s chief executive, Nick Buckles, before Parliament for an emergency hearing.

They grilled him on management failings and reports even more G4S staffers were poorly trained or were failing to report to work at Olympic sites across Britain, forcing police departments to step in to provide additional security in some areas outside London.

“It’s a humiliating shambles for the country, isn’t it?” said David Winnick, a member of the opposition Labor Party.

Buckles replied, “I cannot disagree with you.”