Arsenal manager Arsene Wenger expects Pierre-Emerick Aubameyang to provide "offensive power" to his side when the striker completes a move from Borussia Dortmund.

Aubameyang is expected to wrap up a club-record transfer to Arsenal worth a reported £55.5million before the window closes on Wednesday, the Gabon international having been pictured at the club's training ground.

Arsenal lost 3-1 at Swansea City on Tuesday in a blow to their Champions League qualification hopes and Wenger spoke about the impending arrival of Aubameyang after the match in a video that was apparently posted to the club's official website in error.

The clip was subsequently removed from the website but was circulated widely by social media users, with Wenger excited by the potential of Aubameyang to liven up his side's attack.

"Yes, it is good news," Wenger said of the expected move. "We need people who can give us more offensive power.

"At the moment, we aren't enough going forward and I am convinced he will give us that.

"He has a big challenge in front of him. He wants to do well in the Premier League. It is absolutely good news for us.

"His pace, his finishing. The quality of his runs. His huge physical capacity, that will be important in the Premier League."

Aubameyang's signing is expected to pave the way for Arsenal to sell Olivier Giroud to Premier League rivals Chelsea, who in turn will allow Michy Batshuayi to leave on loan.

Belgium international Batshuayi is likely to complete the transfer merry-go-round by heading to Dortmund as the replacement for Aubameyang.