NEW YORK - More than 100 former US Republican officials and lawmakers endorsed Democratic presidential nominee Vice President Kamala Harris on Wednesday, while calling Republican candidate and former President Donald Trump "unfit to serve again as president".

In a letter shared by the Harris campaign, 111 Republicans, including former officials who served under Ronald Reagan, George H.W. Bush, George W. Bush and Trump, said that despite their disagreements with Harris' policies, "we believe that she possesses the essential qualities to serve as President and Donald Trump does not."

"As president," the letter said, Trump "promoted daily chaos in government, praised our enemies and undermined our allies, politicized the military and disparaged our veterans, prioritized his personal interest above American interests and betrayed our values, democracy and this country's founding documents".

They condemned Trump's incitement of the attack on the Capitol on Jan 6, 2021, saying that "he has violated his oath of office and brought danger to our country."

"Anyone who puts himself over the Constitution should never be President of the United States," the letter quoted former Vice President Mike Pence as saying.

The signatories included two former defense secretaries, Chuck Hagel and William S. Cohen; two former Central Intelligence Agency directors, Michael V. Hayden and William H. Webster; a former director of national intelligence, John D. Negroponte.

Robert B. Zoellick, former president of the World Bank, and eight former members of Congress also endorsed in the letter.

The letter came days after former Vice President Dick Cheney and his daughter Liz Cheney, former Representative and one of Trump's loudest conservative critics, announced they would vote for Harris.