WASHINGTON — President Donald Trump has ordered the release of thousands of classified governmental documents about the 1963 assassination of President John F. Kennedy, which has fueled conspiracy theories for decades.

The executive order Trump signed Thursday also aims to declassify the remaining federal records relating to the assassinations of Sen. Robert F. Kennedy and the Rev. Martin Luther King Jr. The order is among a flurry of executive actions Trump has quickly taken the first week of his second term.

Speaking to reporters, Trump said, “everything will be revealed.”

Trump had promised during his reelection campaign to make public the last batches of still-classified documents surrounding President Kennedy’s assassination in Dallas, which has transfixed people for decades. Trump made a similar pledge during his first term, but ultimately bent to appeals from the CIA and FBI to withhold some documents.

Trump has nominated Kennedy’s nephew, Robert F. Kennedy Jr., to be the health secretary in his new administration. Kennedy’s father, Robert F. Kennedy, was assassinated in 1968 as he sought the Democratic presidential nomination. The younger Kennedy has said he isn’t convinced that a lone gunman was solely responsible for the assassination of his uncle, President Kennedy, in 1963.

The order directs the director of national intelligence and the attorney general to develop a plan within 15 days to release the remaining John F. Kennedy records, and within 45 days for the other two cases. It was not clear when the records would actually be released.

Trump handed the pen used to sign the order to an aide and directed it to be given to Robert F. Kennedy Jr.

Only a few thousand of the millions of governmental records related to the assassination of President Kennedy have yet to be fully declassified. And while many who have studied what’s been released so far say the public shouldn’t anticipate any earth-shattering revelations, there is still an intense interest in details related to the assassination and the events surrounding it.

“There’s always the possibility that something would slip through that would be the tiny tip of a much larger iceberg that would be revealing,” said Larry J. Sabato, director of the University of Virginia Center for Politics and author of “The Kennedy Half-Century.” “That’s what researchers look for. Now, odds are you won’t find that but it is possible that it’s there.”

Kennedy was fatally shot in downtown Dallas on Nov. 22, 1963, as his motorcade passed in front of the Texas School Book Depository building, where 24-year-old assassin Lee Harvey Oswald had positioned himself from a sniper’s perch on the sixth floor. Two days after Kennedy was killed, nightclub owner Jack Ruby fatally shot Oswald during a jail transfer.

In the early 1990s, the federal government mandated that all assassination-related documents be housed in a single collection in the National Archives and Records Administration. The collection of over 5 million records was required to be opened by 2017, barring any exemptions designated by the president.

The order notes that although no congressional act directs the release of information on the assassinations of Robert F. Kennedy or King, those governmental records being made public “is also in the public interest.”

During his first term, Trump boasted that he’d allow the release of all of the remaining records on the president’s assassination but ended up holding some back because of what he called the potential harm to national security. And while files have continued to be released under President Joe Biden, some still remain unseen.

Sabato, who trains student researchers to comb through the documents, said that most researchers agree that “roughly” 3,000 records have not yet been released, either in whole or in part, and many of those originated with the CIA.

The documents released over the last several years offer details on the way intelligence services operated at the time, and include CIA cables and memos discussing visits by Oswald to the Soviet and Cuban embassies during a trip to Mexico City just weeks before the assassination. The former Marine had previously defected to the Soviet Union before returning home to Texas.

King and Robert F. Kennedy were assassinated within two months of each other in 1968.

King was outside a motel in Memphis, Tennessee, on April 4, 1968, when shots rang out. The civil rights leader, who had been in town to support striking sanitation workers, was set to lead marches and other nonviolent protests there. He died at a hospital less than an hour later.

James Earl Ray pleaded guilty to assassinating King. He later though renounced that plea and maintained his innocence up until his death.

FBI documents released over the years show how the bureau wiretapped King’s telephone lines, bugged his hotel rooms and used informants to get information against him. The agency’s conduct was the subject of the recent documentary film, “ MLK/FBI.”

Robert F. Kennedy, then a New York senator, was fatally shot on June 5, 1968, at the Ambassador Hotel in Los Angeles moments after giving his victory speech for winning California’s Democratic presidential primary. His assassin, Sirhan Sirhan, was convicted of first-degree murder and is serving life in prison.

There are still some documents in the JFK collection though that researchers don’t believe the president will be able to release. Around 500 documents, including tax returns, weren’t subject to the 2017 disclosure requirement. And, researchers note, documents have also been destroyed over the decades.