The FBI has released a newly declassified document that looks into connections between Saudi citizens in the US and two of the 9/11 attackers.
Relatives of victims have long urged the release of the files, arguing Saudi officials had advance knowledge but did not try to stop the attacks.
But the document provides no evidence that the Saudi government was linked to the 9/11 plot.
Fifteen of the 19 plane hijackers were Saudi nationals.
Ahead of the declassification, the Saudi embassy in Washington welcomed the release and once again denied any link between the kingdom and the hijackers, describing such claims as "false and malicious".
The document was declassified on the 20th anniversary of the deadliest terror attacks on US soil - almost 3,000 people were killed after four planes were hijacked - and is the first of several expected to be released.
Some families of the victims had put pressure on President Joe Biden to declassify the documents, saying he should not attend Saturday's commemoration ceremonies in New York if he was not prepared to release them.
This 16-page FBI document is still heavily redacted. It is based on interviews with a source whose identity is classified (listed as PII) and outlines contacts between a number of Saudi nationals and two of the hijackers, Nawaf al-Hazmi and Khalid al-Midhar.
The hijackers posed as students to enter the US in 2000. The FBI memo says they then received significant logistical support from Omar al-Bayoumi, who witnesses said was a frequent visitor to the Saudi Consulate in Los Angeles despite his official status at the time as a student.
Mr Bayoumi, the source tells the FBI, had "very high status" at the consulate.
"Bayoumi's assistance to Hamzi and Midha included translation, travel, lodging and financing," the memo said.
The FBI document also says there were links between the two hijackers and Fahad al-Thumairy, a conservative imam at the King Fahad Mosque in Los Angeles. He was described by sources as "having extremist beliefs".
Both Mr Bayoumi and Mr Thumairy left the US weeks before the 9/11 attacks, according to the AP news agency.
The agency also quoted Jim Kreindler, a lawyer for the relatives of 9/11 victims, as saying that the released document did "validate the arguments we have made in the litigation regarding the Saudi government's responsibility for the 9/11 attacks".
Last month, a lawsuit launched by relatives saw several top former Saudi officials questioned under oath.
The administrations of George W Bush, Barack Obama and Donald Trump all declined to declassify the documents, citing national security concerns.
But Joe Biden last week ordered a review of investigative documents, telling officials to release what they could over the next six months.
There has long been speculation of official Saudi links to the plot, given the number of Saudi nationals involved and al-Qaeda leaders Osama Bin Laden's Saudi background.
However, the 9/11 Commission report found no evidence to implicate the Saudi government or senior officials.
The US and Saudi Arabia have long been allies, although the relationship has at times been difficult.
Donald Trump strengthened ties but Joe Biden called Saudi Arabia "a pariah" for its part in the gruesome murder of Saudi journalist Jamal Khashoggi in Turkey.
The BBC's Frank Gardner says Mr. Biden has since softened his stance towards most powerful man in Saudi Arabia, Crown Prince Mohammed bin Salman, reflecting the hard reality of the importance of the alliance.
GACL apologises for power outage at KIA
Water Technology Certificate introduced at St Paul’s School in Kukurantumi
Showing of JoyNews’ ‘Sick Hospitals’ documentary causes stir in Parliament
Gaza receives first airdrop of US humanitarian aid
Akatsi: Man in police custody found dead
Vanuatu parliament welcomes Vanuatu Trade Commissioner to Ghana Prof. Hugh Keku Aryee in historic visit
Ghana has become a ‘no-action, talk only’ country – Theo Acheampong
Man convicted over water meter theft
Anti-LGBTQ Bill: Parliament did not go against the constitution – Sam George
Anti-LGBTQ+ bill: All arguments remain personal opinions until SC makes pronouncement – Joseph Kpemka
Anti-LGBTQ Bill: Provisions in the bill do not impose a cap, gag the media – Sam George
No regrets over move to Swansea in 2015 – Andre Ayew
Anti-LGBTQ+ bill: Ghana has done the right thing by passing the bill – Bokpin
Anti-LGBTQ+ bill is flawed and unconstitutional – Prof Audrey Gadzekpo
15 resolutions, 2 decisions and a ministerial declaration agreed at UNEA-6