Earlier this month, United had held talks with representatives of the Portuguese.
Mourinho, 53, was sacked by Chelsea in December, seven months after winning the Premier League title.
Asked if he will replace Louis van Gaal at Old Trafford, Mourinho said: “That’s the one million dollar question.”
Speaking at a school in Singapore, he added: “Nobody knows and I am the first one not to know. I read so many different things.”
Mourinho has been linked with a return to Serie A side Inter Milan and Spanish giants Real Madrid.
But he said: “Starting next season with a new club and project is probably the best for me.”
The future of Dutchman Van Gaal, 64, has been an almost constant source of speculation in rec