The FBI has released the first of several soon-to-be-declassified documents about its investigation into the September 11th terrorist attacks.
It follows an executive order by US President Joe Biden, requiring the agency to release a number of documents unless the "strongest possible reasons" require them to be held back.
The document released overnight is heavily redacted but details an investigation into whether Saudi officials provided logistical support to some of the alleged 9/11 hijackers.
The 16-page document - from 2016 - contains no firm conclusions, or any evidence that the Saudi government was linked to the attacks.
It does present details of meetings between Omar al-Bayoumi - a Saudi man who was purportedly a Saudi student in the US but whom the FBI has long-suspected of being an intelligence agent - and two of the hijackers.
Mr Bayoumi says a meeting with the two hijackers at a restaurant was simply a "chance encounter".
However, the document also claims he provided logistical support to two hijackers - including "translation, travel assistance, lodging and financing".
A source (referred to throughout the document as 'PII') also told the FBI that Mr Bayoumi had "very high status" at the Saudi consulate.
Most of the 9/11 hijackers were from Saudi Arabia, but the Saudi government has always denied any involvement in the attacks.
The Saudi embassy in the US has welcomed the release of previously classified documents, saying they hope "that a full release of these documents will end the baseless allegations against the Kingdom once and for all".
In a statement ahead of the release, they said: "The Kingdom has always advocated for transparency surrounding the September 11 tragedy.
"No evidence has ever emerged to indicate that the Saudi government or its officials had previous knowledge of the terrorist attack or were in any way involved in its planning or execution.
"Any allegation that Saudi Arabia is complicit in the September 11 attacks is categorically false."
Families of 9/11 of victims have long called for the release of documents about the attack, and claim the release overnight is the first step in release documents that "have been kept secret for years".
The 9/11 Families United group also claims the document "puts to bed any doubts about Saudi complicity in the attacks".
President Biden's executive order requires a number of other documents to be released over the course of the coming months.
The release comes the day after the US marked the 20th anniversary of 9/11, with President Biden attending a series of ceremonies at the sites of the attacks.