After President Trump vowed last year to release all the long-secret files related to the JFK assassination, the administration announced Thursday that some documents will be withheld until October 2021 for national security reasons.

In a White House memo, Trump said that the nation’s intelligence community persuaded him to keep some documents secret because their exposure could harm “identifiable national security, law enforcement, and foreign affairs concerns.”

Trump gave the CIA, FBI and other agencies a deadline of April 24 to release the last remaining documents related to the investigation into President John F. Kennedy’s assassination by Lee Harvey Oswald on Nov. 22, 1963, in Dallas. Last year Trump, who once suggested Sen. Ted Cruz’s father played a role in the assassination, promised he was going to release the entirety of the 5 million pages of records, most of which have been available since the late 1990s.