Manchester United are reportedly chasing Robert Lewandowski and Mats Hummels as they look to strengthen their squad for next season.
The Red Devils are said to be favourites to land forward Shinji Kagawa but have now emerged as contenders for his two Borussia Dortmund teammates as well.
According to the Daily Mail, Sir Alex Ferguson went to watch the trio during Dortmund's 5-2 German Cup victory over Bayern Munich.
Lewandowski's agent Maik Barthel revealed that contract talks between his client and Dortmund have hit a snag and said that Man United are lurking in the shadows.
"The offer from Dortmund is not enough and I can confirm there is interest from Manchester United," the Daily Mail quotes Barthel as saying.
It is believed that the reigning Bundesliga champions will demand around £50m for the players.
