By Andrew Warshaw at the Main Press Centre on the Olympic Park in London

August 7 - The International Olympic Committee (IOC) today launched a strong defence of its strict sponsorship rules after several athletes, mainly from the United States, questioned why they could not mention their individual commercial backers, on whom they rely for funding, on social networking sites or identify them on their uniforms.

Rule 40 of the Olympic Charter says only official Games sponsors can be named and Timo Lumme, the IOC's director in charge of marketing services, says that is how it should remain.

"One of the pillars as regards to the funding of the Olympic Movement are the sponsors, both globally and locally," he told a briefing here.