Manchester United manager Ole Gunnar Solskjaer says the club "know my view" about transfer activity before the window closes on Monday.
While some rivals have added to their squads significantly, United's only signing is Netherlands midfielder Donny van de Beek, who cost £40m from Ajax.
Executive vice-chairman Ed Woodward says matches played behind closed doors have hit the club financially.
"The club has been working," said Solskjaer on Friday.
Borussia Dortmund rejected United's most recent approach for England winger Jadon Sancho, who is Solskjaer's top target. and while there has been interest in Barcelona forward Ousmane Dembele, there has been no suggestion a loan deal for the France international is close.
Porto's Brazilian full-back Alex Telles is another target.
The deadline for international transfers and moves between Premier League clubs is 23:00 BST on Monday, though top-flight sides can still sign players from the English Football League until 17:00 on 16 October.
"They [United] know my view," added Solskjaer. "The transfer window is still open for a little while. If something happens in or out you will get to know.
"There are many ways of improving a team. I keep reading about the players who should be playing instead of the ones who aren't because they are performing well. That tells me I have a strong squad. There is competition for places.
"We need results. That is the only way of affecting the mood at the club - the players and staff. All the rest is short-term moods."
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