The organisers of the 2014 Commonwealth Games in Glasgow have closed the ticket website and phoneline until ongoing problems with sales can be resolved.
Glasgow 2014 said the measure was necessary to address technical issues which had hampered the sales of 100,000 extra tickets since Monday.
The organiser said it was "very sorry".
So far, about 55,000 of the extra tickets have been bought with diving, swimming, mountain biking, track cycling and the triathlon all sold out.
Glasgow 2014 chief executive David Grevemberg told BBC Radio Scotland's Newsdrive programme that the website and phoneline would be unavailable from 18:00 BST on Tuesday until the technical issues had been resolved.
"We have instructed Ticketmaster, our agent for ticketing, to close the Glasgow 2014 website from 6pm until we can be assured that the technical issues that have been experienced by some of the customers and ticket-buyers over the last 24 hours are resolved to our satisfaction.
"We stated his morning that we completely recognise that this is not satisfactory and is something we've taken very seriously.
"From that time, no further customers will be able to access the website until further notice and customers who are either queuing or logged onto the website at this point should be able to complete their session."
Extra tickets for all 17 sports and the opening and closing ceremonies went on sale on a first-come, first-served basis at 10:00 BST on Monday.
It quickly became apparent from comments posted on social media sites that the online site could not cope with demand.
Some people said they been trying to get tickets for up to 24 hours. People also reported problems with the phone booking system.
Others told of successfully getting through online, only to be returned to the queue while attempting to pay.
Disappointed sports fan Peter Charlton told BBC Scotland: "People do want to buy the tickets but at the same time, they do have a life to lead. There I am sitting there seven hours later and still waiting.
"Quite bluntly, it is a farce."
After waiting six and a half hours, Jane Waller managed to get two tickets for the gymnastics and one for the Velodrome.
But as she was about to pay, she was put back into the queuing system.
"I wasn't sure if I'd been charged or not so I ended up having to phone my credit card company," she said.
"It's just a fiasco. I was really looking forward to telling my daughter I had tickets for the gymnastics but unfortunately I haven't now."
Glasgow 2014 was forced to close the site at midnight on Monday to investigate the problem. It re-opened again in the early hours of Tuesday morning but was not glitch free.
Mr Grevemberg said the decision to close the website and phoneline had been taken after the problems persisted for a second day.
"The system we've been using with Ticketmaster is a tried and tested system," he said.
"This particular system was put through a testing regime that was far in capacity than even some of the numbers that we've had.
"The ticket system has not met capacity and has not coped with demand. In the past 28 hours we've gone through a number of technical solutions with Ticketmaster which have not solved the situation."
Mr Grevemberg could not say when the ticket sales would resume but said they would be widely publicised.
He said that about 55,000 of the 100,000 extra tickets had been sold with diving, swimming, mountain biking, track cycling and the triathlon all sold out.
Tickets are still available for other sports and the opening and closing ceremonies.