French club Metz are ready to lodge a complaint with UEFA after their proposed deal with West Ham for Diafra Sakho collapsed.

It is understood a fee of £3.5million and personal terms had been agreed for the striker but West Ham have stepped back from a deal for the 24-year-old angering the French side in the process.

FC Metz have released a statement condemning West Ham United's 'unacceptable lack of respect'.

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Complaint: FC Metz are furious after West Ham pulled out of a £3.5m deal for Diafra Sakha

According to the statement released by Metz, West Ham switched from wanting a permanent transfer to a loan deal with the option to buy.

Metz have branded West Ham 'disrespectful' for their conduct during talks and are considering their legal options as Sakho missed the club's opening Ligue 1 fixture on Saturday, a goalless draw with Lille, to undergo his medical.

'The English club unilaterally decided to propose a loan deal with an option to purchase instead of a permanent deal, which does not correspond to FC Metz's expectations and contradicts all the terms that had been agreed last week between the two clubs,' a statement from Metz read.

'FC Metz regret this clear lack of respect, which is unacceptable, from West Ham towards FC Metz and also the player.

'As a result, FC Metz reserve the right to approach the international sport court and assert their rights and defender their interests. FC Metz had released Diafra Sakho from his professional duties during matchday 1 of the Ligue 1 championship by giving him leave to take a medical in England to complete the last stage of the deal.'

West Ham are interested in Sunderland striker Connor Wickham, but not for the £10m asking price

Metz lawyers are understood to have given West Ham until 12noon to stand by the proposed agreement for Sakho.

If that deadline passes they will push for West Ham to be punished with a points reduction in their complaint to UEFA

The player will return to Metz today.

West Ham maintain an interest in Sunderland's Connor Wickham but are reluctant to match the £10m valuation.