US President Donald Trump has withdrawn former vice president Kamala Harris's Secret Service protection, officials said Friday, in what critics called a fresh act of revenge against his political rivals.

The Republican's move comes just weeks before Democrat Harris is set to go on a tour to promote a new book about her failed presidential campaign against Trump last year.

The Secret Service customarily protects vice presidents for six months after they leave office, a period that ended on 21 July for Harris.

But then-president Joe Biden approved a year-long extension for Harris in a previously undisclosed order -- which 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 Allen, a senior advisor to Harris, told AFP.

Democrats rallied behind Harris over the move, especially in California where she previously served as a senator.

Los Angeles Mayor Karen Bass said it was "another act of revenge following a long list of political retaliation" by Trump, according to a statement reported by US media.

"This puts the former Vice President in danger and I look forward to working with the Governor to make sure Vice President Harris is safe in Los Angeles." 

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

Trump has withdrawn protection for former national security advisor John Bolton -- whose house was raided by FBI agents in a classified documents probe last week -- former secretary of state Mike Pompeo and former top US military officer Mark Milley.

In March he pulled government bodyguards from Biden's son Hunter and daughter Ashley.

Stripped of clearances

He has also stripped other officials and former officials -- including Biden himself -- of their security clearances to receive sensitive information.

While Harris, 60, has kept a low profile since losing the election, she is scheduled to go on tour this fall to promote her memoir "107 Days" about her short presidential run. 

The book, which Harris said she wrote with "candor and reflection", will be published by Simon & Schuster 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.

The move to withdraw her protection comes even though the Trump administration has repeatedly stressed 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 1 September, said CNN, which first reported the move.

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

Biden and his wife Jill get protection for life under federal law as a former president and his spouse, but his adult children were not so lucky.

Trump in March said it was "ridiculous" that Hunter Biden had a security detail of up to 18 people.

But after his first term in office from 2017 to 2021, billionaire Trump issued an order giving a six-month extension of Secret Service protection to all four of his adult children and three senior administration officials.

by Danny KEMP