Mephis Depay, Matteo Darmian, Bastian Schweinsteiger and Morgan Schneiderlin have already been lured to Old Trafford during the close-season as United strive to become Premier League title challengers, while the likes of Real Madrid duo Sergio Ramos and Karim Benzema continue to be linked with United.
And United boss Van Gaal still wants to strengthen, as he told MUTV: "I hope so. No, we are not finished yet, I think.
"We need a balance in the selection and I think we still need to improve at least two positions and we shall do that when it is possible.
"But we shall only buy when the player can give a contribution to our level.
"And, of course, that is in the eyes of our staff, but I have to have confidence that he can cope with the rhythm of the Premier League."
