The Leeds United Supporters Trust says the proposed takeover of the Championship club has fallen through.
In June, Leeds said a group of investors - unnamed, but believed to be from the Middle East - had been granted due diligence, and it had been widely expected that a deal would be concluded soon afterwards.
But on Thursday, the fans' trust issued a statement on Twitter, which said: "The Leeds United Supporters Trust can confirm that the deal to buy the club has now collapsed.
"We will be making a more detailed statement later on once we have had the chance to establish more."
Reports in Yorkshire said concerns about the prospects of the takeover grew on Wednesday when the Elland Road chief executive, Shaun Harvey, flew to Monaco to meet chairman Ken Bates in an attempt to reach a conclusion on the deal.
The Yorkshire Post said the Bahrain media had claimed a group of investors, headed by Leeds supporter Mubarak Al-Khalifa, had believed they were close to completing a deal for the club.
Al-Khalifa was part of a consortium that failed in a takeover attempt in 2003. At the time, he told reporters that Leeds "mean everything to me - I was born to support them. Those who are closest to me, my friends and my family, know what Leeds United mean to me".