London 2012 black market ticket claims 'depressing'
Claims of Olympics tickets being sold on the black market are "deeply depressing", London 2012 chairman Lord Coe has said.
It would not be possible to probe the claims before the Games, he said.
Lord Coe's comments came after the Sunday Times accused 27 officials and agents representing 54 countries of being involved in corruption.
More than one million tickets were distributed overseas among all nations taking part in London 2012.
The International Olympic Committee (IOC) has strict rules to combat touts, but it said it is the responsibility of individual National Olympic Committees to make sure its allocation is sold only within its own country.
'Breaking rules unacceptable'
The newspaper reported some tickets were being offered for sale at 10 times their face value.
Lord Coe said: "[At] 39 days to go to the Olympic Games, I think it is highly unlikely we would be able to fully understand what these allegations are about and whether there is any truth in them, but we do take it very seriously.
"It's a deeply depressing scenario if its proven to be the case."
On Sunday, Sir Menzies Campbell - a member of the Olympic Board that helps to oversee London 2012 - said any tickets known to have been sold at more than face value should be banned and offending countries should not be awarded tickets in future Games.
Earlier, IOC executive board member Denis Oswald said: "If you know you are breaking rules and still do it, it is unacceptable."
People who were aware they were breaking rules "should no longer belong to the Olympic movement", he added.
In May, a senior Ukrainian Olympic official, Volodymyr Gerashchenko, was suspended after he told a BBC London reporter posing as a UK tout he would have up to 100 tickets to sell for cash.
BBC London has also previously uncovered how some official ticket resellers were flouting the London Olympic Games and Paralympic Games Act, designed to stop Olympic tickets entering the black market.