Arsenal have spoken to all their players after Alexandre Lacazette, David Luiz, Nicolas Pepe and Granit Xhaka were pictured breaking social distancing guidelines.
Lacazette was too close to someone valeting his car, while Luiz and Xhaka were having a kickabout in a park.
Pepe was seen playing football with some friends.
The quartet, along with the rest of the Gunners squad, have been reminded of their responsibilities.
UK government guidelines say you can only exercise on your own or with people you live with. Also, if you have to go outside, you should stay more than 2m (6ft) apart from anyone other than members of your own household.
Earlier this week, Tottenham's Serge Aurier and Moussa Sissoko apologised for training together despite the coronavirus restrictions.
Spurs also did not adhere to guidelines when manager Jose Mourinho was pictured holding a one-on-one training session in a park with midfielder Tanguy Ndombele, while defenders Ryan Sessegnon and Davinson Sanchez were filmed running side-by-side.