West Ham will have to up their bid for Gokhan Tore as "?Bestiktas have slapped a £17m price tag on the versatile midfielder, according to "?Fanatik.
The former Chelsea youngster attracted the attention of the London club some time ago and, according to reports, negotiations have been taking place with a £12m deal having been discussed.
Tottenham and West Ham target Michy Batshuayi says he is drawn to the Premier League#SSNHQ pic.twitter.com/9fayHeSzpd
However, the Turkish club are adamant not to let the 24-year-old Turkish international join the Hammers so easily, raising the bid by another £5m.
Besiktas president Fikret Orman said: "Gokhan Tore is an important part of our team.
"We will take place in the next season in the Champions League and are in favour of having him with us."
West Ham and former Besiktas manager Slaven Bilic, who knows the player well having worked with him at the Istanbul club during his tenure, has previously failed to bring him to London following a rejected £7.4 million bid in January.
Tore, who has been been capped 26 times for Turkey, has graced the Premier League before, playing for West Ham's London rivals Chelsea during his youth career.
Mario Gomez has scored 28 in 41 outings for Be?ikta? in all competitions this term. A starter for Germany? #EURO2016 pic.twitter.com/UdFNPNJz6y
He was then moved on to German side Hamburg in 2011 making 22 appearances, despite playing an important role for the Blues' Under-21s.
In 2014, following a disappointing move to Russian side Rubin Kazan, Tore was loaned to Besiktas before securing a permanent deal through a series of impressive appearances and, this season, helped them to the Super Lig title with four goals and six assists in 24 games.