The agent of Sporting Lisbon striker Ricky van Wolfswinkel admits new contract talks have stalled.

A confirmed target for Manchester United, Liverpool and Tottenham, Van Wolfswinkel scored 20 goals last season.

Louis Laros told Record: "We are waiting for Sporting. There is still no progress in increasing the value of the buy-out clause that the club want to include.

"I have heard rumours in the media about interest in the player from foreign clubs."