Manchester City manager Pep Guardiola should not wear a yellow ribbon because "we don't want political symbols in football", FA chief executive Martin Glenn has said.
The Spaniard has been wearing the ribbon on the touchline in support of imprisoned politicians in Catalonia.
The Football Association (FA) charged him last month after two warnings.
"You can't have, and we don't want, football equipment to display political symbols," said Glenn.
He was speaking at the International Football Association Board (Ifab) meeting in Zurich, where the use of video assistant referees was approved.
"To be very clear, his yellow ribbon is a political symbol, it's a symbol of Catalan independence," said Glenn, who stated "there are many more Spaniards, non-Catalans" who are upset by it.
"We have re-written Law Four of the game so that things like a poppy are OK.
"But things that are going to be highly divisive, and that could be strong religious symbols - it could be the Star of David, it could the hammer and sickle, it could be a swastika, anything like Robert Mugabe on your shirt - these are the things we don't want."
The former Barcelona coach was given two formal warnings about the issue in December before being charged by the FA in February.
He has until 18:00 GMT on 5 March to respond to a charge of breaching kit and advertising regulations.
"Before a manager, I am a human being," the 47-year-old Spaniard said.
"They [the FA] know I'll wear the yellow ribbon always. It's not about politicians, it's about democracy; it's about helping the people who didn't do absolutely anything."
The charge was triggered when Guardiola again wore the ribbon on his jacket on the touchline during City's shock FA Cup defeat by Wigan although he is free to wear it elsewhere.