The organization told RIA Novosti it is looking into allegations the record, which was confirmed Sunday, did not include the 26,000 people local officials in Vladivostok said formed the human flag, which was certified as beating the previous record of 24,000 people, set in Pakistan.
Local bloggers said they doubted the numbers released by the city and an expert who viewed photos of the event said there appeared to be only 9,600 people comprising the human flag.
"Following concerns raised around the counting method used during the recently adjudicated record for largest human flag on Sunday, July 7 in Vladivostok, Russia, Guinness World Records will be undertaking a thorough review of all evidence received," Guinness said in a written statement to RIA Novosti. "This will involve gathering expertise from a number of sources and is likely to take a number of weeks to complete."
"During this investigation the current record holder's status remains the same and once our review is completed we will be in a position to comment further," Guinness officials wrote.
A Vladivostok city administration spokesman declined to comment, RIA Novosti said.