President Joe Biden is ordering the widespread declassification of information collected during the U.S. investigation of the Sept. 11 terrorist attacks following growing pressure to do so from family members of the victims.

The order lays out specific timelines over the next six months for the release of the documents, with some set to be released as early as next week’s 20th anniversary of the terror attacks. Information should only remain classified if its release would pose a clear national security risk, and shouldn’t remain classified “in order to conceal violations of law, inefficiency, or administrative error or to prevent embarrassment to a person, organization, or agency.”

“Information collected and generated in the United States Government’s investigation of the 9/11 terrorist attacks should now be disclosed, except when the strongest possible reasons counsel otherwise,” Biden said in an executive order directing the declassification.

The White House has been under intense pressure ahead of the 20th anniversary from families of victims and first responders who believe the classified documents may show a link between Saudi Arabian leaders and the attacks.

Nearly 1,800 people affected by the attacks issued a statement last month opposing Biden’s participation in any memorial events this year unless he released more documents, saying that as a candidate Biden pledged to be more transparent and accused his administration of having ignored their letters and requests.

One group, 9/11 Families United, celebrated the announcement Friday and called it a step towards getting justice for their loved ones lost in the attack.

“We are thrilled to see the President forcing the release of more evidence about Saudi connections to the 9/11 Attacks,” said Terry Strada, whose husband, Tom, was killed in the World Trade Center. “We have been fighting the FBI and intelligence community for too long, but this looks like a true turning point.”

The 9/11 Commission report found no evidence implicating Saudi leaders in the attack, but said Saudi nationals played a major role in funding Al Qaeda. The Saudi government has denied any connection to the attacks.

Rep. Adam Schiff, D-Calif., chairman of the House Intelligence Committee, said he supports the release of the documents. Legislation was introduced introduced in Congress to declassify the information.

“As we near the 20th anniversary of that terrible day, the families of those who were killed, and all Americans, have a right to know the full story, and the passage of time has mitigated concerns over sources and methods,” Schiff said in a statement.

Three previous presidents had declined to declassify the documents with the Trump administration invoking the state secrets privilege in 2019 to justify keeping documents classified.