The Red Devils are likely to be linked with a host of players in the coming weeks as the January transfer window presents Mourinho with the chance to bolster his squad midway through the season.
Manchester United have found themselves in stuttering form this season and they have struggled to string together consistent performances in the Premier League.
Indeed, Manchester United are currently seventh in the Premier League table and 16 points behind leaders Manchester City after 14 games.
There have been reports in Italy recently suggesting that Manchester United have already had a bid rejected by Napoli for Koulibaly.
Mourinho was asked in a news conference over the weekend whether Manchester United were indeed interested in Koulibaly or not.
However, he did not give much away, and was quoted as saying by Metro: “I cannot answer to your question.
“If is true, if is not true, I cannot answer to your question, maybe your question is the first one about the market and maybe the next press conference I have two more questions, and maybe the next press conference I have three more.
“The only thing I can tell you is Koulibaly is a Napoli player. And I don’t speak about players from other clubs.”
Meanwhile, Mourinho will be focused on preparing his Manchester United team for their crunch Premier League clash against Arsenal at Old Trafford on Wednesday night.
The Red Devils were held to a 2-2 draw in the Premier League by Southampton at the weekend and they have only won two of their last five Premier League games.
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