So far this summer Benfica defender Victor Lindelof and Everton striker Romelu Lukaku have arrived at Old Trafford.
Mourinho still wants two more signings and a move for Inter's Perisic is reportedly edging towards completion.
How Manchester United could line up next season
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Last week, United enjoyed a breakthrough in negotiations with Internazionale in the pursuit of Ivan Perisic and are thought to be closer to agreeing a final fee for the winger.
A deal is expected to be concluded in the next few days for the 28-year-old Croatian international, and will likely come to £48m.
Personal terms had already been agreed with Perisic, although Inter had been completely unmoving on the size of the fee.
But Mourinho is still keeping his cards close to his chest.
Asked for an update on the transfer after the 2-1 friendly win at Real Salt Lake, Mourinho said as he left the press conference: “No idea. No idea my friend. No idea.”
Chelsea defensive midfielder Nemanja Matic is another reported target for Mourinho, while it is understood United maintain an interest in Tottenham's Eric Dier.
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