The White House has released 2,891 documents related to the assassination of John F. Kennedy that have long been kept secret.

The trove of files was published on the National Archives website on Thursday night, and produced revelations and prompted more questions about the fateful day in Dallas in 1963.

The documents revealed that Lee Harvey Oswald was being tracked by the FBI before JFK was killed and met a KGB agent in Mexico City's Soviet Embassy two months before the shooting.

An unidentified man also called the FBI and said they were going to kill Oswald - just 24 hours before he was gunned down by Jack Ruby while in police custody.

But not all of the records were released, because President Trump has kept some back so federal agencies can black out portions.

He is allowing intelligence, law enforcement and military agencies to take the next six months to justify their requests to redact specific pages.

A White House official told DailyMail.com during a conference call that while Trump wants to remove the 'veil' of secrecy regarding the 1963 killing, he has 'no choice today but to accept those redactions rather than risk irreversible harm' to the country.

President Donald Trump has let the National Archives release 2,800 pages of material related to the John F. Kennedy assassination, but he's letting the FBI and CIA redact – black out – portions of other documents for the next six months

The trove of files was published on the National Archives website on Thursday night, but President Trump has kept some back so federal agencies can black out portions

One of the documents is a transcript of a conversation with FBI Director J. Edgar Hoover over a threat made against Lee Harvey Oswald

President Kennedy was assassinated in 1963; a 1992 law set October 26, 2017 as the deadline for the government to release all its information about who killed him and why – but gave the White House a loophole for national security

John F. Kennedy and wife Jackie arrived at Love Field during a campaign tour on day of his assassination

'There does remain sensitive information in the records,' the official said, often 'related to the identity of individuals involved, in their roles as informants.'

The official also said some edits would be made to hide 'activities that were conducted with foreign partner agencies.'

One of the documents released on Thursday night included a transcript of a conversation with FBI Director J. Edgar Hoover concerning a threat made against Lee Harvey Oswald.

'There is nothing further on the Oswald case except that he is dead. Last night, we received a call in our Dallas office from a man talking in a calm voice and saying he was a member of a committee organized to kill Oswald,' Hoover says.

He also says he was assured by Dallas police that they would give the shooting suspect protection, but Jack Ruby managed to kill him on November 24, 1963, two days after JFK's assassination.

Other files not related to the shooting show that Robert Kennedy was sent a memo when he was Attorney General warning him that a book detailing his affair with Marilyn Monroe was about to be published.

There is also more insight into the elaborate plots to kill communist leaders in Latin America, including Fidel Castro.

The White House said that about 2,800 files released on Thursday to the National Archives and Records Administration are only those that will be released 'in full' – and agencies will be able to roll out partially edited documents over the next week.

'The vast majority of the requests came from the FBI and CIA,' a White House official said.

The administration has essentially 'kicked the can a bit,' a White House aide admitted after a conference call with reporters on Thursday.

'We can't keep this up forever,' he admitted, 'but it's better to get it right than to do it quickly.'

Trump tweeted Wednesday about the forthcoming release of JFK assassination files, showing no hint that he would allow government agencies to hide parts of some documents from public view

Bystanders looked on as Jacqueline Kennedy reached over to help her husband who lay on the rear of a car after being struck by an assassin's bullet as his motorcade traveled through Dealey Plaza

Although Washington closed the case shortly after JFK's death, there have been several conspiracy theories, including that the murder plot involved Cuban leader Fidel Castro and there has long been rumors of a second shooter

Hours after he killed Kennedy, Lee Harvey Oswald talked to the media as he was led down a corridor of the Dallas police station for questioning

The Dallas Police Department mug shots of Lee Harvey Oswald following his arrest for possible involvement in the John F. Kennedy assassination and the murder of Officer J.D. Tippit, who he killed after shooting the president

The White House has set April 26, 2018 as the new deadline for spy and law enforcement agencies to justify each and every redaction.

'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,' Trump wrote in a memo to the National Archives.

'I have no choice – today – but to accept those redactions rather than allow potentially irreversible harm to our Nation's security.'

'To further address these concerns, I am also ordering agencies to re-review each and every one of those redactions over the next 180 days. 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,' he added.

White House press secretary Sarah Huckabee Sanders said in a statement that Trump 'has demanded unprecedented transparency from the agencies and directed them to minimize redactions without delay.'

After the shooting, Secret Service agent Clinton Hill (pictured) ran from a car directly behind the President's and jumped onto the vehicle in order to further protect JFK and the First Lady

Trump during the 2016 campaign promoted information about Rafael Cruz, Sen. Ted Cruz's father, suggesting he may have been involved in the JFK assassination

That revised time-frame will leave him open to claims of a new cover-up as he find s himself stuck between students of the killing who want every scrap of information and intelligence agencies that are counseling restraint.

The National Archives has more than 5 million pages of records related to the 1963 Kennedy assassination including photos, films, recordings and artifacts.

About 88 percent of it has been fully available to the public since the late 1990s, and another 11 percent has been released with sensitive portions blacked out.

The remaining one percent has remained totally secret.

Under a 1992 law passed after Oliver Stone made a conspiracy-laden JFK assassination movie, everything was set for an October 26, 2017 release.

The law's framers built in a national security loophole, and Trump has been convinced by America's top cops and spymasters to take it.

Kennedy's assassination has attracted conspiracy theories ever since he was gunned down in Dallas on Nov. 22, 1963.

This 1964 photo shows the bipartisan presidential commission that investigated the Kennedy assassination; from left are: Rep. Gerald R. Ford, R-Mich.; Rep. Hale Boggs, D-La.; Sen. Richard Russell, D-Ga.; Chief Justice Earl Warren, chairman of the group; Sen. John Sherman Cooper, R-Ky.; John J. McCloy, a New York banker; Allen W. Dulles, former director of the Central Intelligence Agency; and J. Lee Rankin, general counsel for the commission

Shortly before the Indiana primary election last year, Trump promoted a National Enquirer story about Rafael Cruz, the father of his chief rival at the time, Texas Senator Ted Cruz.

The story featured a hazy photograph that it claimed might show Rafael Cruz standing next to JFK assassin Lee Harvey Oswald.

'His father was with Lee Harvey Oswald prior to Oswald's being – you know, shot. I mean, the whole thing is ridiculous,' Trump told Fox News at the time.

'What is this, right prior to his being shot, and nobody even brings it up. They don't even talk about that. That was reported, and nobody talks about it,' Trump said.

No matter how much is ultimately revealed about the 1963 killing in Dallas, it probably won't be enough to satisfy conspiracy theorists who believe someone other than Lee Harvey Oswald was involved in the assassination, including the government itself.

This image provided by the Warren Commission is an overhead view of President John F. Kennedy's car in Dallas motorcade on Nov. 22, 1963, and was the commission's Exhibit No. 698. Special agent Clinton J. Hill is shown riding atop the rear of the limousine. President Donald Trump is caught in a push-pull on new details of Kennedy's assassination, jammed between students of the killing who want every scrap of information and intelligence agencies that are said to be counseling restraint. How that plays out should be known on Oct. 26, 2017, when long-secret files are expected to be released. (Warren Commission via AP)

Warren Commission Exhibit No. 697 showed Kennedy at the extreme right on the rear seat of his limousine during the Dallas motorcade where he was killed

View of people as they cry and wait for news outside Parkland Hospital, where President John F Kennedy had been taken following his assassination

Lyndon Johnson was sworn in on Air Force One alongside JFK's widow just hours after the President was shot. Jackie Kennedy refused to change out of her blood-soaked Chanel suit

The Warren Commission in 1964 reported that Oswald was a lone gunman, and another congressional probe in 1979 found no evidence to support the theory that the CIA had been involved. But other interpretations, some more creative than others, have persisted.

For example, Roger Stone, a close Trump ally, advanced the unsubstantiated and widely disdained theory that Lyndon Johnson, who became president upon Kennedy's death, was involved in it.

Stone is not sure key documents will see the light of day. He said that 440 documents related to the assassination, released by the National Archives in July, were so heavily redacted "on the basis of 'national security' that they are useless." Stone said he's lobbied Trump personally to release all remaining materials and believes the CIA is pushing the president to keep some secret.

Led by members of the Metropolitan Police Department of the District of Columbia the Chairmen of the Joint Chiefs, and the US Marine Corps band the funeral procession of slain President John F. Kennedy approaches the entrance to Arlington National Cemetery after passing the Lincoln Memorial and crossing over the Potomac River on Memorial Bridge

JFK was buried on November 25, 1963 as America watched on. Jackie Kennedy stood solemnly with her children Caroline Kennedy and John Jr

Members of the Kennedy family at the funeral of assassinated president John F. Kennedy at Washington DC. Three-year-old John Kennedy saluted his father

The gunshots that the Warren Commission said killed Kennedy almost immediately inspired theories about whether Oswald had been the lone gunman who, with extraordinary luck by any measure, had hit his target.

As the nation mourned in disbelief, Oswald was shot and killed in police custody by Jack Ruby - forcing Americans to consider whether their government was hiding what it knew of the assassination.

The event remains in the nation's living memory for a significant slice of the country. Forty-nine million Americans, or 15 percent of the country, are age 65 and over, according to the Census Bureau. They were around age 11 or older at the time.

The Warren Commission did little to settle the matter. Theories abounded that Oswald's murder was a cover-up for a conspiracy or government ineptitude. The deadly aim of a lonely, alienated gunman seemed hard to fathom.

Fidel Castro waves to the people in Havana in January 1959 (left). Castro and other combatants started a revolutionary war against the U.S.-backed regime of Fulgencio Batista in December 1956 and over the next two years they conducted a guerrilla struggle that won increasing popular support