According to respected German outlet Bild, Arsenal have upped their offer from £48.3million to £50.9m.
Dortmund are understood to want a swift conclusion to the situation and have been holding talks with Arsenal chief executive Ivan Gazidis, chief scout Sven Mislintat and contract negotiator Huss Fahmy.
The Bundesliga side have slapped a £61.5m price tag on Aubameyang which Arsenal are reluctant to meet.
Earlier today, Arsenal boss Arsene Wenger was asked if he was confident of completing a deal for Aubameyang and replied: “Confident or not confident, I don’t know.
“You never know how close you are.
“This is the kind of thing – he is one of the possible movements, but we have other things in mind as well. We have plenty of opportunities and the final decision is not made.
“At the moment we are not close to any deal, Aubameyang or anybody else.”
Despite the speculation surrounding him, Aubameyang has trained with his team-mates this week.
Any move to Arsenal could include Olivier Giroud moving in the opposite direction.
Giroud has been out of the Arsenal team this season after losing his place to Alexandre Lacazette and wants to ensure a spot in France’s World Cup team.
When asked if Giroud would be part of any deal, Wenger added: “The negotiations are not as far as that.”
Should Aubameyang join Arsenal, he would link up with Henrikh Mkhitaryan, having played with him at Dortmund.
And Wenger reckons the pair are capable of rekindling their relationship due to their quality.
He said: “You look at players and what their qualities are, what they can give to the team. When they are good players, they can always play together.”
Meanwhile, Aubameyang is due in court in Germany next Monday to give evidence in the trail over the Dortmund team bus bombing.
Aubameyang was with the deal when exploring devices were let off near the bus, injuring Marc Bartra.
Aubameyang is due to be a witness in court and there are concerns this could delay his transfer to Arsenal, with the judge worried he will not be able to attend if he is in England to complete a deal.
