Coutinho has had a transfer request rejected by Liverpool in the last 24 hours after learning they would not consider selling him to Barca.
Klopp, angry with Barca's attempts, fired a warning regarding Lionel Messi.
He told DAZN: "It's pretty simple, until today it seemed impossible but now there is a list of players with the amount of the release clauses of those players of FC Barcelona. That of Lionel Messi amounts to €300M.
"In just a month everything became possible ... They just fell asleep (regarding PSG and Neymar). Because, who would pay €300M? But this is what could happen."