Washington DC - President Joe Biden marked the 60th anniversary of John F. Kennedy's assassination Wednesday with a call for Americans to unite in carrying forward the slain Democrat's optimistic vision.

"In life and in death, President Kennedy changed the way we saw ourselves – a country full of youthful hopes and ambition, steeled with the seasoned strength of a people who've overcome profound loss by turning pain into unyielding purpose," Biden said in a statement.

"He called us to take history into our own hands, and to never quit striving to build an America that lives up to its highest ideals."

Kennedy (46) was shot dead by Lee Harvey Oswald while riding in a motorcade in Dallas on November 22, 1963 – a milestone in US history that sent shockwaves around the world and spawned a cottage industry of conspiracy theories.

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Biden recalled that he was just leaving a class at university when he learned of JFK's death, which he said "awakened a generation" to the importance of civil rights, including voting access and equal pay.

The president urged today's Americans to remember the unfulfilled promise of Kennedy's presidency "not only as a tragedy, but as an enduring call to action to each do all we can for our country."

Both under Biden and his predecessor Donald Trump, the National Archives has released tens of thousands of previously classified documents related to the Kennedy assassination.

The decision to declassify was an attempt finally to squash conspiracy theories that Oswald was not acting alone but as part of a broader plot – an idea given new popularity with Oliver Stone's popular, conspiratorial film JFK.

On June 30 this year, the White House said that it had completed its review of all the materials. According to the National Archives, 99% of the entire archive is now public.