Nearly 3,000 records have been released about the assassination
US President Donald Trump has delayed the release of some "sensitive" files about the assassination of John F Kennedy.
Mr Trump released 2,891 records but, after requests mostly from the CIA and FBI, said he had been left with "no choice" but to keep approximately 300 others secret.
In a memo, he said: "Executive departments and agencies have proposed to me that certain information should continue to be redacted because of national security, law enforcement and foreign affairs concerns.
"I have no choice, today, but to accept those redactions rather than allow potentially irreversible harm to our nation's security."
Those records will be reviewed further over the next six months.
Mr Trump added: "At the end of that period, I will order the public disclosure of any information that the agencies cannot demonstrate meets the statutory standard for continued postponement of disclosure."
There has been much speculation about what might be contained in the previously unseen files regarding the fatal shooting of President Kennedy in Dallas on November 22nd 1963.
Correspondent Cordelia Lynch said the delay would "only deepen intrigue in a story already rich with mystery".
She added: "Historians and analysts I have spoken to are saying they weren't expecting a smoking gun of sorts, they don't believe there is a second gunman but do want to know more about the CIA's involvement (in the assassination)."
The documents were published on the US National Archives website and they showed how federal agents had chased down tips, however, thin, in the days after the assassination.
Among the revelations was:
In 1964, the Warren Commission concluded Lee Harvey Oswald was the only gunman and a 1979 congressional inquiry found no evidence to support the claim of CIA involvement. But suspicion has persisted, nevertheless.
A statement months ago from the National Archives had said it assumed the records would be "tangential" to what is already known about the killing.
President George HW Bush signed a law in 1992 requiring all documents on the assassination be released within 25 years, unless doing so would harm intelligence, law enforcement, military operations or foreign relations.
Mr Trump had confirmed just days ago that he would meet this deadline - October 26th.
The move by the Bush administration had been driven in part by the furore caused by Oliver Stone's 1991 film JFK, which claimed there was a vast conspiracy to kill the president.
Read the full tranche of documents here