Football’s ruling body Fifa has filed a complaint against ticket website Viagogo over the company’s “opaque and deceptive” practices.
In a statement, Fifa warned it would cancel any World Cup tickets identified as having been purchased through the Swiss-based website.
It said it was fighting ticket resales to “prioritise the safety and security of fans”.
The 2018 Fifa World Cup begins in Russia on 14 June.
Fifa said it had filed the complaint against Viagogo with the public prosecutor’s office in Geneva on Monday following “numerous complaints”.
Tickets to the tournament could be legitimately purchased through Fifa’s website only, it added.
Earlier this year, Fifa successfully filed for a temporary injunction against Viagogo for advertising tickets to the World Cup before they had been allocated or issued.
This is not the first time that Viagogo has faced controversy.
The site is currently under investigation by the UK’s National Trading Standards, after the company was found to have failed to make compulsory fees “sufficiently clear”.