Arsenal captain Laurent Koscielny has refused to travel with the squad for their preseason tour of the US.
The 33-year-old France defender is out of contract at the end of the 2019-20 season and is a reported target for French clubs Bordeaux, Rennes and Lyon.
"We are very disappointed by Laurent's actions, which are against our clear instructions," said Arsenal.
"We hope to resolve this matter and will not be providing any further comment at this time."
Bordeaux have reportedly offered Koscielny a three-year deal.
