Kylian Mbappe could leave PSG as a free agent next summer (ABACA/Shutterstock)

Manchester United, Liverpool and Real Madrid are on alert as Kylian Mbappe has decided not to trigger an extension option in his contract with Paris Saint-Germain, according to reports in France.

PSG had announced last year that 24-year-old’s new deal, which worth in excess of £547 million, would run until June 2025.

However, L’Equipe report that the final year of the contract is based on an option which Mbappe has decided not to take up and has until the end of July to do so.

That decision means the France international, who has scored 40 goals in all competitions this season, could be available as a free agent next summer.

The pressure is now on PSG to decide whether to sell their prized asset this summer, or risk losing him for nothing at the end of next season.

L’Equipe report that Real Madrid, Liverpool and Manchester United are all monitoring Mbappe’s situation at PSG and could make a move if the French club decide to sell.

Kylian Mbappe has not taken up the option of extending his deal with PSG (Getty)

When asked about his future at PSG last month, Mbappe said: ‘The next step? Winning the Champions League.

‘I have already made a final, semi-final, quarter-final, round of 16… I have done everything but win. That’s all I need. Where? In Paris. I’m a Parisian and under contract. So it’s PSG.’

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PSG, meanwhile, are already facing the prospect of losing both Lionel Messi and Neymar this summer.

Messi will leave the club once his contract expires, while it’s understood that Neymar is now looking to leave PSG with both Chelsea and Manchester United considering a move.

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Mbappe could now leave as a free agent next summer.