Borussia Dortmund have warned Chelsea and AC Milan they will not let Shinji Kagawa leave Germany without a fight.
Kagawa, 23, has been earning rave reviews for the Bundesliga champions and has been tipped to make a big-money transfer.
Chelsea have been strongly linked with the talented midfielder, while AC Milan have also been following his progress, and both clubs were reported to be ready to make their move at the end of the season.
But Dortmund are desperate to keep Kagawa, who is out of contract next summer, and their general manager Hans-Joachim Watzke has confirmed the club are planning to open negotiations over a new long-term deal.
Watzke said: "I think he will still be playing at Dortmund beyond the end of next season, but you can never be sure. We want to keep him and extend his contract. He wants to go to England? I don't know, but I keep hearing things in the press."