Some of the highly anticipated secret documents containing details of the John F. Kennedy assassination have been released by the National Archives, more than a half-century since the US president was fatally shot in Dallas, Texas.

The 25-year deadline was set for Thursday, October 26, and while many of the documents were released, the entire trove was not made available by President Donald Trump. Trump said late Thursday that he had "no choice" but to accept the concerns of intelligence agencies, such as the FBI and CIA, according to the Associated Press.

At the request of the CIA and FBI, Trump has delayed some of the JFK files from being fully declassified for at least another six months, the AP reported. The 2,800 documents Trump approved for release are available to search on the National Archives website.

The only person with the power to prevent the release of the documents was Trump, who announced last week that the release would go ahead unimpeded.

The circumstances of JFK's death have fuelled conspiracy theories for years, with many believing shooter Lee Harvey Oswald did not actually kill the president, while others are convinced that the investigation into his murder was impeded by a cover-up orchestrated by intelligence agencies.