Manchester United's on-loan winger Bebe has been sidelined for around six months after tearing the anterior cruciate ligament in his left knee, Turkish club Besiktas said Wednesday.

Bebe, 21, was injured while playing for Portugal under-21s in Slovakia on Tuesday and will require surgery, the Turkish first division club said in a statement on its website.

Club doctor Devrim Uygun said: "We have been informed that Bebe has a tear on his anterior cruciate ligament.

"We have contacted officials at his club Manchester United. We will make a joint decision over where the operation should take place."