Brentford have told Manchester United they will have to return with a larger offer if they want to sign Bryan Mbeumo after rejecting an overall package worth £62.5 million ($85.7 million), sources have told ESPN.
United have made Mbeumo a priority signing and have stepped up negotiations with Brentford in recent days.
Brentford, however, are holding out for more than £62.5m -- including add-ons -- currently on the table, believing the forward's value has increased significantly after hitting 20 Premier League goals last season.
There are indications from Brentford that interested clubs will have to go beyond the £65 million mark to agree a deal for the 25-year-old.
United and Brentford are set to hold further talks, although United, according to sources, have insisted privately they will not be held to ransom.
There is money to spend to strengthen Ruben Amorim's squad -- even without European football next season -- but sources have told ESPN they will remain "disciplined" in negotiations over transfer fees and wages.
They have already signed Matheus Cunha after triggering the £62.5 million release clause in his contract at Wolves. Cunha scored 15 Premier League goals last season and, at 26, is older than Mbeumo.
Despite the setback, United remain confident that Mbeumo wants to move to Old Trafford.
There remains hope that a deal can be agreed, which would allow the Cameroon international to join the squad for the start of preseason training on July 7.
