Switzerland's attorney general office is reviewing 133 reports of suspicious financial activity in connection to Russia and Qatar's successful bids for to host the 2018 and 2022 World Cup finals.
The number has increased since August, when the office reported it was investigating 103 suspected cases of corruption at FIFA, world football's organising body that is based in Zurich.
Both nations have denied wrongdoing, but Switzerland's Money Laundering Reporting Office is continuing to look into the awarding of the bids.
"These reports are related to the ongoing criminal proceedings around the allocation of the Football World Cup 2018 and 2022," a spokesperson told Reuters.