Borussia Dortmund are stepping up their interest in Mainz defender and Arsenal target Abdou Diallo.

According to Bild, Dortmund have tabled a €22 million bid for the player as they look to secure his signature.

The defender, who impressed at Mainz last season, has been a transfer target for both teams for quite some time.

Arsenal had considered the player as a back-up plan to Sokratis, should a deal fall through with Sven Mislintat a huge admirer of Diallo.

However, Sokratis’ impending move to Arsenal is expected to be confirmed in the coming weeks and Diallo could be considered as his long-term replacement at Dortmund.

Lucien Favre is looking to re-shape the Dortmund defence this summer and Diallo has been one of the club’s key transfer targets.

The 22-year-old played 30 times in all competitions last season for a Mainz side who narrowly avoided relegation.