Borussia Dortmund have warned Arsenal against bidding for Pierre-Emerick Aubameyang, insisting the striker is not for sale.
Gabon international Aubameyang has been lauded as one of the Bundesliga's best strikers after netting 26 times last season.
Arsenal reportedly failed with a bid of £28.7million for the former St Etienne player and reports in the German press suggest the Gunners will come back in with a renewed bid of over £30million.
But, having allowed Ciro Immobile to join Sevilla, Dortmund are determined to hold on to Aubameyang and are hopeful of extending his deal at Signal Iduna Park.
Speaking to German magazine Kicker, Dortmund's sporting director Michael Zorc said: "We rely heavily on Aubameyang - that is no secret.
"I've heard a lot about this (a transfer to Arsenal) but I can say very clearly that it is blocked for him. He is simply not for sale."
Aubameyang has three years left on the five-year contract he signed at Dortmund in the summer of 2013.