He told BBC's Newsnight he did not want to go to Old Trafford "because I don't want to" and that he signed for United because "something happened".
Asked why he signed for the club, he added: "I don't know, something happened, you know? I don't want to play for them."
When pushed on why he signed for United, Mikel said: "I never wanted to play for United. I was forced to."
And when quizzed on who forced him, he said: "Some people."
Mikel's attitude to Chelsea was very different and when asked if he wanted to play for the Blues, he said: "Yeah, because I love Chelsea and I am going to be happy when I am there. They (Chelsea) know."