Arsenal are set to open disciplinary proceedings against Laurent Koscielny after he refused to join the club on their pre-season tour of the USA, according to Sky sources.

The 33-year-old France international is out of the contract at the end of the season and it is understood he has asked to be released from his deal so that he can return to France.

The club said in a statement on Thursday: “Laurent Koscielny has refused to travel to the US for our pre-season tour.

“We are very disappointed by Laurent’s actions, which are against our clear instructions.

“We hope to resolve this matter and will not be providing any further comment at this time.”