"Lionel Messi is a Barcelona player," the City manager stated during Friday's press conference.
"I have a huge gratitude for what Barcelona did for me as a player in the academy and as a manager. I have said many times that I would like Leo to finish his career there."
Messi's relationship with Barcelona is strained after he wasn't granted a transfer over the summer. He also complained on Wednesday he's "tired" of being blamed for the club's problems.
His irritation with his situation in Catalonia and Thursday's news of Pep Guardiola signing a new two-year contract at the Etihad Stadium heightened speculation that the player and tactician could reunite at Manchester City.
Despite his apparent preference for Messi to remain loyal to Barcelona, Guardiola didn't rule out the possibility of the 33-year-old leaving for another club when his Camp Nou deal expires at the end of the 2020-21 season.
"His contract finishes this year and I don't know what will happen in his mind," the former Barcelona and Bayern Munich boss said. "Right now he is a Barcelona player and the transfer market is in June and July.
"We have incredible games and targets and things we would like to achieve. That is the only thing in our mind. The rest I cannot say anything."
Current Barcelona handler Ronald Koeman admitted earlier on Friday that he doesn't know where Messi's future lies.