The Scottish FA says "clubs are still convening training sessions against the guidance" of the governing body amidst the coronavirus pandemic.
Echoing government warnings to the public about heeding social distancing advice, the SFA have reminded member clubs "in the strongest possible terms" to "desist" training activities.
All senior football has been suspended since 13 March.
"Please stop it," was SFA chief executive Ian Maxwell.
"While many of the instances have been anecdotal, I have seen it for myself this weekend.
"I urge everyone involved in the game to do what we can to safeguard public health.
"The message from the first minister, which was reiterated today, could not be clearer when she said 'the advice that is being given to people is not to be seen as optional'. That applies to football as it does across society."
Maxwell added that Scotland's national clinical director professor James Leitch "outlined the importance of exercise but that it is done alone, or in very small family groups, whilst observing social distancing guidelines, and advised people to look at the many online classes now offered".