WASHINGTON — The Trump administration decided Thursday to declassify a key name long sought by relatives of 9/11 victims who are suing Saudi Arabia over allegations of that country's involvement, but declined to release the name publicly.

The name of the individual, which the 9/11 families believe may support their allegation of Saudi involvement in the terror attacks, will be disclosed to the plaintiff's lawyers under a protective order. The order makes it illegal for those attorneys to release the name to the public, meaning the identity of the individual will remain a secret — at least for now.

The decision by the FBI and the Justice Department was a partial victory for the 9/11 families, who have been fighting in court to compel the Trump administration to hand over the name. Terry Strada, who chairs the group 9/11 Families & Survivors United for Justice Against Terrorism, called it "a good result."

“The families are dedicated to getting to the truth, and we shouldn't have to beg for this sort of basic information, or be kept in the dark, about the Saudi role in the attacks," Strada said in a statement.

Still, the administration did not declassify other documents the 9/11 families have sought as part of their lawsuit, although the FBI said more documents could be produced in the future.

The FBI pointed out that the name of the individual had been the families' top priority, calling it "the primary piece of information that the plaintiffs in the 9/11 litigation have been seeking."

The Saudi Embassy in Washington did not immediately respond to a request for comment. The White House, which earlier referred all questions about the matter to the Justice Department, also did not immediately respond to a request for comment.

The long-awaited decision involved whether to disclose the name of a person who allegedly directed two men in California who assisted hijackers in the 9/11 attacks. The 9/11 families and their lawyers believe the person may be a Saudi official, but the name was redacted when a 2012 summary of the FBI's inquiry into the matter was previously released.

But the decision pitted President Donald Trump's efforts to show he's seeking justice for 9/11 victims against his desire to maintain close ties with Saudi Arabia, already strained in the wake of the killing of journalist Jamal Khashoggi by Saudi agents last year. Trump has worked to preserve the relationship with the Saudis despite widespread criticism in Congress of Crown Prince Mohammed bin Salman's leadership.

Lawyers for the 9/11 families have sought to get the unredacted version released by the FBI, and a deadline for the Justice Department to decide whether to release was delayed several times at the government's request, most recently until Thursday.

In the end, the Justice Department declined to invoke the "state secrets" privilege, a provision in U.S. law that allows the government to refuse to release information in lawsuits that could undermine national security. The FBI said in a statement that the decision was made "in light of the extraordinary circumstances of this particular case."

"The Attorney General has decided not to assert the State Secrets privilege over that name," the FBI said.

Advocates for the 9/11 families were given some reason for optimism this week when Jim Kreindler, a prominent attorney representing some of the 9/11 families, was a guest of the White House at a ceremony at the Pentagon marking the anniversary of the attacks, several people familiar with his attendance tell NBC News.

White House officials have previously maintained that the decision about how to handle the legal matter rests with Attorney General William Barr. But the significant implications for the U.S. relationship with close partner Saudi Arabia, combined with Trump's past record of seeking to influence Justice Department decisions, has raised speculation that he might get more personally involved.

Although 15 of the 19 attackers in the 9/11 attacks were Saudi citizens and mastermind Osama bin Laden was born there, Saudi Arabia's government has long denied involvement in 9/11. The 9/11 Commission that investigated the attacks found it likely that Saudi government-funded charities did fund the attacks but did not find evidence that the government or senior Saudi officials were involved.

The lawsuit against Saudi Arabia was enabled by a 2016 law called the Justice Against Sponsors of Terrorism Act that allowed for a civil suit against a foreign state if it supports international terrorism against Americans or their property. Former President Barack Obama vetoed the law, warning it could create a precedent for the U.S. or its officials to be sued in foreign courts, but Congress voted to override his veto.