At least a dozen San Antonio police officers face disciplinary action for wearing Donald Trump campaign gear.

FOX's Rachel Sutherland reports:

The police officers were seen on video wearing red "Make America Great Again" hats as they greeted the Republican Presidential nominee at the airport this week:

(Trump) "Thank you fellas." (Police) "Thank you sir."

San Antonio Police Chief William McManus says the city bans all public employees from getting involved in politics while on the job and that he expects his officers to know better than to give the appearance of endorsing a candidate while on duty or in uniform, regardless of the political campaign.

Rachel Sutherland, FOX News.

Follow Rachel Sutherland on Twitter: @SutherlandFOX