Tevez has been at West Ham since August 2006

The striker's move to Old Trafford is in danger of breaking down because the two clubs cannot agree a way forward.

Now Kia Joorabchian has decided to hit out, accusing the Hammers of making "promises and assurances, which they have not acted upon or performed".

He says he plans to take the issue up with both the Football Association and Fifa in a bid to resolve the issue.

Joorabchian issued a statement late on Thursday on behalf of his company Media Sports Investments (MSI), which read: "West Ham have consistently provided private assurances while at the same time making contrary statements to the public at large.

"We can no longer allow these inconsistencies to continue unaddressed.

"We wish to make clear that at all times it has been our intention to find an amicable solution and Carlos Tevez has, at no time, acted improperly in relation to his move to Manchester United as he was given permission via his representatives to talk to other clubs to reach an amicable agreement.

We are not sure whether we will have him signed in time for the new season United chief executive David Gill

"Over the last six months West Ham have made repeated promises and assurances which they have not acted upon or performed. It is now time for these inconsistencies to be brought to an end.

"We see no alternative but to bring the true circumstances to the attention if a higher authority to aid a rapid conclusion to this issue."

A special 'dispute resolution chamber' will be set up by Fifa, possibly within a fortnight, to effectively determine who currently owns Tevez - West Ham or Joorabchian.

United chief executive David Gill has expressed his confidence that Tevez will eventually become a United player.

But he said: "Hopefully the case will be heard on an expedited basis but we are not sure whether we will have him signed in time for the new season.

"It may take up to two weeks for the body to be formed, all the paperwork has to be put together and then the case has to be heard.

"Even given that timetable we hope by the time the new season kicks off, Carlos will be training at Carrington."

With Fifa set to look at the transfer after they were asked by both United and West Ham to intervene, it is understood the authorities Joorabchian refers to are both the FA and the world governing body.

Tevez has been in Manchester since Tuesday night, but West Ham refused permission for him to have a medical at Old Trafford.

The Hammers insist they are still waiting to receive an offer for Tevez.

And the Premier League says a deal must be done between United and West Ham but not Joorabchian who owns Tevez's economic rights.

West Ham released a statement on Tuesday, which said: "No agreement has been reached in relation to Carlos Tevez."

Under Premier League rules, one club is not allowed to give a player a medical unless his current club agree.

Tevez flew into Manchester on Tuesday after finishing on the losing side with Argentina in Sunday's Copa America final against Brazil, while Manchester United are on a pre-season tour in Japan.

United's legal expert Maurice Watkins has remained in England as efforts to resolve the dispute intensify.

606: DEBATE I hope this dispute can be settled sensibly and fairly - but I fear that may not be possible J

The Premier League has insisted West Ham, which holds Tevez's registration, must receive the majority of the reported �30m fee rather than Joorabchian.

Last week, a Premier League spokesman stated: "Any deal for Carlos Tevez has to be done directly with West Ham United.

"They hold the registration and we will not transfer the registration unless a deal is done directly with the club."

West Ham were only allowed to keep playing Tevez last season after assuring the Premier League all third-party clauses in the player's contract had been severed.