David Moyes travelled to Germany last Friday and sat with a representative of Kroos' agent as Bayern beat Borussia Monchengladbach 2-0.

And that has seen the rumour mill go into overdrive, with reports suggesting United could be about to launch a £25m offer for the 24-year-old.

Guardiola was asked about speculation linking Kroos with the Red Devils after the club's match again Stuttgart and did nothing to downplay talk of a potential move.

He said: "He is an important player but things can move fast in football.

"Here today, gone tomorrow."

Negotiations over a contract extension with Bayern have stalled with Kroos' agent Volker Struth saying the proposed terms are unacceptable.