San Antonio's police chief vows to discipline more than a dozen officers seen in a Donald Trump campaign video wearing "Make America Great Again" caps while in uniform.

In a statement posted to the city's Twitter account, Chief William McManus said the officers "displayed poor judgment" and violated city policy by wearing the campaign hats while on duty. McManus said the officers "will be disciplined appropriately," but didn't elaborate.

"I expect them to know better than to give the appearance of endorsing a candidate while on duty and in uniform, regardless of the political campaign or the candidate," McManus said in the statement.

A video on Trump's Twitter account shows at least 14 members of his motorcycle escort wearing the signature red caps after escorting Trump to San Antonio International Airport on Tuesday. In the 25-second video, Trump is heard saying "Thank you, fellas" to the officers. Several officers then thank the Republican presidential nominee and gave him a thumbs-up sign.

City Attorney Andrew Segovia sent a letter Tuesday to the Trump campaign asking that the video be removed from its social media platforms.

"We make the request because similar security is provided to all political candidates," he wrote. "Impartiality and neutrality with respect to the person being protected is essential to effectively carrying out their role as assigned security."