According to The Athletic, Arsenal have made contact with Thomas Partey's camp and informed them of their intention to trigger his 50 million euro release clause.
It is understood that Arsenal are making the necessary arrangements to complete the deal before the 11pm deadline today.
Atletico Madrid indicated previously that they will not accept anything below 50 million euros for his transfer and will only let him go if the clause is triggered.
Arsenal already know the personal terms he wants and reports say that will not be a problem.
Partey was a key member of Diego Simeone's side last season with over 40 appearances in all competitions.