​Arsenal have confirmed that chief executive Ivan Gazidis has left the club to join AC Milan, with Raul Sanllehi and Vinai Venkatesham promoted to new senior roles within the club.

Head of football relations Sanllehi has been appointed as head of football, while Venkatesham, currently chief commercial officer, becomes managing director.

"It has been a pleasure working with Ivan," said Josh Kroenke, deputy chairman of Arsenal's majority owner Kroenke Sports, in an ​official statement. "We will miss the wisdom, insight, and energy he brought to our club on a daily basis over the past decade. 

"We are confident we have outstanding people in Raul and Vinai, and we look forward to working with them and coach Unai Emery to continue to move the club forward on and off the pitch."

Sanllehi joined ​Arsenal in February after 16 years at Barcelona, where he was director of football. Venkatesham has been Arsenal since 2010, having previously worked on the 2012 London Olympics.

Gazidis, who has worked at Arsenal since 2009, also issued ​his own statement to the fans of the club, describing this as "the hardest decision of my life."

Gazidis will leave Arsenal by the end of October. On December 1 he will become ​AC Milan's new chief executive, responsible for leading the club’s day-to-day football, business and commercial operations.

"On behalf of the Board and the entire AC Milan community, we proudly welcome Ivan Gazidis to the club," said Milan's executive chairman Paolo Scaroni ​in a statement. "The CEO role is one we have prioritised from day one of this project and one we have worked diligently upon to get right. 

"Ivan Gazidis will bring an unparalleled level of business acumen and football industry experience to the club."