A 1992 law required all government records related to the assassination to be “publicly disclosed in full” within 25 years. The deadline was Thursday.

“I have no choice,” Trump said in a memo on Thursday night explaining why he had put around 300 of the classified documents under a six-month review.

He cited “potentially irreversible harm” to national security if he allowed all of the records were made public.

Later in the evening, the US Archives posted online the 2800 documents approved for release.

Officials say Trump will impress upon federal agencies that “only in the rarest cases” should JFK files stay secret after the review.

Despite having months to prepare for disclosures that have been set on the calendar for 25 years, Trump’s decision came down to a last-minute debate with intelligence agencies – a tussle the President then prolonged by calling for still more review.

Much of Thursday passed with nothing from the White House or National Archives except silence, leaving unclear how the Government would comply with a law requiring the records to come out by the end of the day – unless Trump had been persuaded by intelligence agencies to hold some back.

White House officials say the FBI and CIA made the most requests within the government to withhold some information.

No blockbusters were expected in the last trove of secret files regarding Kennedy’s assassination on November 22, 1963, given a statement months ago by the Archives that it assumed the records, then under preparation, would be “tangential” to what’s known about the killing.

But for historians, it’s a chance to answer lingering questions, put some unfounded conspiracy theories to rest, perhaps give life to other theories – or none of that, if the material adds little to the record.

JFK experts also believe the files will provide insight into the inner workings of the CIA and FBI – but they stress that it will take weeks to mine the documents for potentially new and interesting information.

Some of the documents are related to Harvey Lee Oswald’s mysterious six-day trip to Mexico City right before the assassination, scholars say. Oswald said he was visiting the Cuban and Soviet Union embassies there to get visas, but much about his time there remains unknown.

The documents are also believed to contain details about the arrangements the US entered into with the Mexican government that allowed it to have close surveillance of those and other embassies.

Researchers were frustrated by the uncertainty that surrounded the release of the records for much of Thursday.

“The government has had 25 years-with a known end-date-to prepare #JFKfiles for release,” University of Virginia historian Larry Sabato tweeted in the afternoon. “Deadline is here. Chaos.”

-AP