Arsenal's Pierre-Emerick Aubameyang talks hit stumbling block as Borussia Dortmund insist replacement is signed BEFORE sanctioning £53m move*.Borussia Dortmund want to sign a new

Arsenal's move forPierre-Emerick Aubameyanghas hit a stumbling block afterBorussia Dortmundinsisted they would not letthe striker leave without having a replacementlined-up.

Arsenal chief executive Ivan Gazidis and head of recruitment Sven Mislintat have flown toGermanyin an effort to complete their swoop for the 28-year-old striker.

The Gunnershave already had a £43million offer for Aubameyang rejected, though Arsenal will return with a improved offer. But Dortmund are driving a hard bargain.