Jack Ruby told an FBI informant to “watch the fireworks” on the day President John F Kennedy was assassinated, the latest release of JFK files reveals.

Ruby, who went on to shoot and mortally wound Lee Harvey Oswald two days later, made the comments hours before the President was killed in Dallas, Texas.

Although the President was assassinated on 22 November 1963, the interaction between Ruby and the FBI informant, identified as Bob Vanderslice, was not officially relayed to the FBI until March 1977.

What are the JFK files?

“The informant stated that on the morning of the assassination, Ruby contacted him and asked if he would ‘like to watch the fireworks’,” the FBI record stated.

“He was with Jack Ruby and standing at the corner of the Postal Annex Building facing the Texas School Book Depository Building, at the time of the shooting.

“Immediately after the shooting, Ruby left and headed toward the area of the Dallas Morning News Building, without saying anything to him.”

Vanderslice told the FBI that after Ruby was arrested for killing Oswald, he was also arrested on an unrelated criminal charge and got to know him better at the Dallas County Jail.

Ruby died in 1967 while he was still incarcerated.

The assassination of JFK – in pictures Show all 8 1 / 8 The assassination of JFK – in pictures The assassination of JFK – in pictures President John F. Kennedy and his wife Jacqueline Kennedy ride with secret agents in an open car motorcade shortly before the assassination, 22 November 1963 Getty The assassination of JFK – in pictures President John F. Kennedy and his wife Jacqueline Kennedy prior to his assassination Keystone/Getty The assassination of JFK – in pictures Kennedy is struck by an assassin's bullet as he travels through Dallas in a motorcade In the car next to him is his wife Jacqueline and in the front seat is Texas governor John Connally Three Lions/Hulton Archive/Getty The assassination of JFK – in pictures The view from the sixth floor window of the Texas School Book Depository in Dallas, from which Lee Harvey Oswald is thought to have assassinated Kennedy. This photograph was taken approximately one hour after the assassination Hulton Archive/Getty The assassination of JFK – in pictures Lee Harvey Oswald during a press conference after his arrest in Dallas. Lee Harvey Oswald was killed by Jack Ruby on 24 November on the eve of Kennedy's burial AFP/Getty The assassination of JFK – in pictures Lyndon B. Johnson takes the oath of office as President of the United States on the day of Kennedy's assassination. Jackie Kennedy is stood next to Johnson Getty The assassination of JFK – in pictures Kennedy's funeral procession goes into Arlington Cemetery in Washington Newsmakers/Getty The assassination of JFK – in pictures Kennedy's casket sat in the East Room of the White House Newsmakers/Getty

Donald Trump ordered the release of 2,800 files relating to the assassination of President Kennedy and the documents have been published in batches on the National Archives website.