The Secret Service customarily protects ex-VPs for six months after they leave office, a period that ended on July 21 for Harris, the defeated Democratic presidential candidate last year.

But then-president Joe Biden approved a year-long extension for Harris in a previously undisclosed order that Trump has now terminated, a senior White House official told AFP on condition of anonymity.

Harris's office also confirmed the move.

"The Vice President is grateful to the United States Secret Service for their professionalism, dedication, and unwavering commitment to safety," Kirsten Harris, a senior advisor to Harris, told AFP.

While Harris has kept a low profile since losing the election, the 60-year-old is scheduled to go on tour this fall to promote a book she has written on her failed presidential bid. The travel will force her to appear often in public. 

Harris's inside look at her short presidential run against Trump is titled "107 Days." The memoir, published by Simon & Schuster, will be released on September 23 in the United States.

The first woman to serve as vice president of the United States, Harris became the Democratic nominee after Biden, now 82, withdrew from the race amid concerns about his cognitive health.

Harris said she wrote the book with "candor and reflection" and promised a "behind-the-scenes account" of the campaign.

The move to withdraw her protection comes even though the Trump administration has repeatedly spoken of the need for security for current officials following the assassination attempt that the Republican survived in July 2024 in Butler, Pennsylvania.

Trump sent a signed memo ordering Homeland Security Secretary Kristi Noem to "discontinue any security-related procedures previously authorized by Executive Memorandum, beyond those required by law" for Harris from September 1, said CNN, which first reported the move.

The Secret Service did not immediately respond to a request for comment.

Since taking office in January, Trump, 79, has taken similar measures against a long list of his perceived enemies and political opponents.

He has stripped other officials and former officials of their security clearances to receive sensitive information -- including Joe Biden himself -- targeted law firms involved in past cases against him and pulled federal funding from universities.

Biden and his wife Jill get protection for life under federal law as a former president and his spouse, but Trump in March withdrew government bodyguards from Biden's son Hunter and daughter Ashley.

Trump at the time said it was "ridiculous" that Hunter Biden had a security detail of up to 18 people.

Trump has also withdrawn protection for former national security advisor John Bolton, former secretary of state Mike Pompeo and Anthony Fauci, who led the country's fight against Covid-19.