US President Donald Trump has revoked protection for former Vice President Kamala Harris' Secret Service protection, according to a White House official, as cited by multiple US media outlets on Friday.

President Donald Trump revoked Kamala Harris' Secret Service protection on Thursday, according to a copy of a letter reviewed by CNN.

"The Vice President is grateful to the United States Secret Service for their professionalism, dedication, and unwavering commitment to safety," the adviser said as reported by NBC News.