The National Security Agency improperly collected phone call records of Americans last fall, months after a previous breach that compelled the agency to destroy millions of records from the contentious program, documents released Wednesday revealed.

The redacted documents, obtained by the ACLU in a Freedom of Information Act lawsuit, do not indicate how many records NSA improperly collected in the October breach, nor which telecommunications provider submitted the improper data.

"These documents provide further evidence that the NSA has consistently been unable to operate the call detail record program within the bounds of the law," the ACLU said in a letter to Congress this week lobbying for an end to the program.

The letter says elements within the Office of the Director of National Intelligence concluded the October violations had a "significant impact" on privacy and civil rights, but that the Americans affected were not told of the breach.

The program burst into the international spotlight in 2013, when renegade NSA contractor Edward Snowden leaked information on U.S. surveillance techniques. Federal courts subsequently rejected the mass collection of American phone records, but Congress then passed the USA Freedom Act, which allows the collection with limits.

Patrick Toomey, a staff attorney with the ACLU’s National Security Project, said there is "no justification" for continuing to provide such powers to the NSA.

Massive breach:Ex-NSA contractor pleads guilty to hoarding information

“These documents further confirm that this surveillance program is beyond redemption and a privacy and civil liberties disaster,” Toomey said in a statement. “The NSA’s collection of Americans’ call records is too sweeping, the compliance problems too many and evidence of the program’s value all but nonexistent."

The program collects call records but does not include content of the calls. Last June, the NSA acknowledged that data obtained from a telecommunications service provider included some records the agency was not authorized to receive. Since it could not feasibly separate what was properly obtained data, the agency said it would delete hundreds of millions of call data records dating back to 2015.

NSA spokesman Greg Julian, responding to a request for comment Wednesday from USA TODAY, declined in an emailed statement to discuss specifics of the October issues. But he said that since the June announcement "NSA identified additional data integrity and compliance concerns." Julian said the issues have been addressed and reported to congressional oversight committees.

Julian did not speak to reports that use of the program had been suspended, saying only that "this is a deliberative interagency process that will be decided by the administration."