United and Chelsea have both been linked in recent days with a move for Lewandowski, with Sky Sports claiming the two Premier League clubs have spoken to his representatives over a potential move.

The Poland captain is reported to be unhappy at Bayern and his agent said earlier this week that coach Carlo Ancelotti offered his client a lack of support in the race to finish ahead of Pierre-Emerick Aubameyang as last season's top scorer in the Bundesliga.

However, Bayern have issued a statement to Sky Deutschland saying that Lewandowski is not for sale while warning clubs to stay clear of their player.

The statement read: "Robert Lewandowski is under contract at Bayern and only recently renewed his deal until 2021. Bayern Munich waste no thought on a Lewandowski move.

"There are no talks with other clubs, and there won't be any. If other clubs negotiate with players who are under long-term contracts, they risk FIFA punishment. The agent also confirmed to us that he has not held any contract talks."

Lewandowski ended up missing out on becoming the Bundesliga's top scorer to Aubameyang last season, and he said earlier this month: "I wasn't completely satisfied with the way my team helped me. Immediately after the last game, I was angry and disappointed with my team. That was the feeling I had."

Lewandowski joined Bayern from rivals Dortmund in 2014 and signed a new contract to keep him at the club until 2021 in December.