Both clubs finished below United last season in the Premier League yet Mourinho claims they are projected as "serial winners" despite failing to land a trophy since 2012 and 2008 respectively.
Pushed on whether there would be any ins or outs on Thursday, Mourinho added: "The information I have is no (nothing will happen)".
'I said during pre-season - it looked like I was saying something absolutely out of order, something insane - but I repeat: pre-season is hard when you don't have your players to work, it's as simple as that'.
Sources told ESPN FC on Wednesday that while United were still pursuing a centre-back, but the chase has become problematic during the final hours of the window.
Mourinho warned last weekend that a "difficult season" could lie ahead if they failed to strengthen the squad before the deadline. As it stands, Alderweireld and Maguire are considered too expensive, while Bayern Munich have knocked back a loan move for Boateng.
The lack of new signings will compound issues surrounding his squad for the start of the Premier League season.
Mourinho heads into the Leicester match with a hefty injury list, including key midfielders Nemanja Matic and Ander Herrera, while a host of other stars of only recently returned from their break after World Cup duty.
"They returned on Monday", he said.
"I think it'll be tough but if they were to go of the Champions league and they had free weeks after Christmas, Saturday to Saturday they could be a real threat this season to City". 'When I listen, when I read, it's hard to believe we finished second because you are capable of making people who finish second (sound like we) were relegated.
"It is hard to believe that we finished second because you are capable of making people that finish second look like they were relegated, and people who win nothing, finish below us, and you make them look like serial winners".
"Is hard for me to understand, to feel, to believe we finish second - which I keep saying, and it is sometimes hard to believe, that I won eight championships and three Premier League's but I keep feeling the second last season was one of my biggest achievements in the game". "I won eight championships and three Premier Leagues but I keep feeling the second last season was one of my biggest achievements in the game".
Koreas prepare for summit as North asks USA to ease sanctions
Secretary of State Mike Pompeo and North Korean Foreign Minister Ri Yong Ho on the sidelines of a regional summit in Singapore. Washington has said that sanctions will not be lifted until Pyongyang fully and finally dismantles its nuclear weapons.
Sweep of Yankees shows Red Sox can do 'damage,' too
For the Boston Red Sox , they just need to continue doing what they have done since April, which is winning baseball games. As SNY warns, "The time is now for the Yankees to make their push, especially with a tougher September in the future.