The National Crime Agency (NCA), Britain’s equivalent of the FBI, contacted the Scottish Football Association (SFA) in the run-up to tonight’s game in London.
It is understood there were worries about patterns in Asian betting markets, which seemed to be targeting a number of international friendly games scheduled for this evening.
There is no suggestion that players from either Scotland or Nigeria are involved, but the NCA spoke to the SFA’s security officer, Peter McLaughlin, to make him aware of its concerns.
Bookmakers have also been warned to be on the lookout for any suspicious activity following the NCA tip-off.
SFA chief executive Stewart Regan, who is in London for the game, said preparations were going ahead as normal.
“We have been liaising with the relevant authorities, the National Crime Agency and Fifa, and will be preparing for the match as normal,” he said.
Tonight’s match is being played at Craven Cottage, home of Fulham FC, and will see the Scots take on a Nigerian side which will kick off its World Cup campaign against Iran on
16 June. Chelsea midfielder John Obi Mikel and on-loan Liverpool striker Victor Moses are among the Premiership stars expected to turn out for the African side.
A spokesman for the NCA said: “We will, from time to time, provide operational detail necessary for public reassurance purposes.”
He said the NCA “does not routinely confirm or deny the existence of specific operations or provide ongoing commentary on operation activity”.
Last year, a number of arrests were made by the NCA as part of an investigation into match-fixing in English football.
The NCA said the focus of the operation was a suspected international betting syndicate.
Despite concerns over tonight’s matches, anti-crime agency Europol yesterday said match-fixing was not a “major problem” in European football.
Europol has signed a co-operation agreement with the sport’s European governing body Uefa to deal with the issue of fixing.
“I still don’t think it’s a major problem in European football, not from what I see,” Rob Wainwright, director of the European anti-crime agency, said.
“But we are sending a message that we want to make sure it doesn’t become one.”
He said that Europol was working on nine investigations into match-fixing, but gave no details.
Last year, Mr Wainwright said that hundreds of matches had been fixed in a global betting scam run from Singapore.
He said about 680 suspicious matches had been identified by European police forces and Europol, including qualifiers for the World Cup, European Championship and the Champions League.
Uefa says it monitors around 32,000 professional games in European club competition and national leagues each year for suspicious betting patterns that could indicate a match has been manipulated.
Uefa president Michel Platini has branded match fixing a “scourge”.