LONDON -Sports fans attending the London Olympics were told on Sunday to avoid non-urgent text messages and tweets during events, because the overloading of data networks was affecting television coverage.
Commentators on last Saturday's men's cycling road race were unable to tell viewers how far the leaders were ahead of the chasing pack, because data could not get through from the Global Positioning System devices travelling with the cyclists.
It was particularly annoying for British viewers, who had tuned in hoping to see a medal for cycling's sprint king, Mark Cavendish.
Many inadvertently made matters worse by venting their anger on Twitter at the lack of information.
An International Olympic Committee (IOC) spokesman said that the network problem had been caused by the messages sent by the hundreds of thousands of fans who lined the streets to cheer on the British team.
"Of course, if you want to send something, we are not going to say, 'Don't, you can't do it', and we would certainly never prevent people (from doing so)," he said.
"It's just - if it's not an urgent one, please kind of take it easy."
Other events due to take place on London's roads include the men's and women's marathon and triathlon.
A surge in the use of mobile phones to access the Internet as well as take and send photos and videos has made London 2012 the first true "social- media Games", but also puts pressure on the networks.
The host broadcaster, the BBC, is enabling fans to see many events live on their smartphones.
Mobile operators and infrastructure companies had said that they expected to be able to meet the extra demand.
The IOC spokesman said that it appeared that the problem lay with oversubscription on one particular network and talks had taken place in an attempt to share more of the data.
Official 2012 Olympic communications-services provider BT, Vodafone and O2, owned by Spain's Telefonica, said that they had not seen any network problems.
Mr Steven Hartley of Ovum Telecoms Strategy said that, while mobile capacity was being upgraded at transport and crowd hot spots, spikes in demand at peripheral sites could prove disastrous.
Television coverage is in the hands of the Olympic Broad-casting Services, created by the IOC to ensure uniform coverage at all Games. ' The IOC spokesman conceded that asking people not to send messages at key moments "may not have an awful lot of effect".