Besiktas are one of the clubs interested in signing Mohamed Salah this season. Having left Liverpool in June this year, the Egyptian forward is weighing up his options on the market to determine his next destination.
Turkey, however, has lost ground in recent weeks amid negotiations with the player's representatives.
Following the World Cup, Besiktas kept talks going with Salah's representatives in an effort to reach a figure that would make a move to Turkey feasible.
With his Liverpool contract having expired, the Egyptian would arrive at his new club without a transfer fee. Even so, the player's camp are demanding financial compensation, in the form of a signing bonus and commission, to seal the transfer.
Besiktas accuse Salah's agent of 'illegal' demands
The latest demands from Salah's agent, Ramy Abbas, have unsettled Besiktas, who have already formalised an offer to sign the player.
According to officials at the Turkish club, the forward's agent is responsible for stalling negotiations with 'illegal demands', particularly regarding the figures related to commission.
Regulated by law, such commissions are common in negotiations between club, player and agent. However, according to Besiktas sporting director Onder Ozen, Abbas is demanding a larger cut than the one already set out in the 34-year-old's contract.
'Requests began to arrive that would bring the flow of information and the financial side to a standstill,' Ozen said. 'I can assume that a respected athlete like Salah is unaware of this.'
Salah weighs up Besiktas offer and other proposals on the market
Besiktas' offer at this stage is final. The club do not intend to enter into a bidding war with the player and his representatives over this signing.
While the figures remain on the table for a move to Turkey, Salah is also considering other proposals from his representatives, principally from clubs in Saudi Arabia and Major League Soccer.
'The offer is on the table,' the Besiktas official said. 'If a response to that offer arrives, it can be assessed, but there will not be another one.'
Besiktas' idea had been to pair Salah with Leandro Trossard, signed from Arsenal this window, to recreate a Premier League connection, even if the pair would be representing different clubs.
Alongside them, former Liverpool forward Darwin Nunez, a possible target for Barcelona, has also been linked with a move to Besiktas in recent days.