(CNN) The FBI ran afoul of constitutional privacy protections in some of its uses of an electronic surveillance tool, the secret federal surveillance court said in an opinion released Tuesday.

The rebuke by a judge serving on the Foreign Intelligence Surveillance Court came in a 2018 ruling that was part of the regular certification process for the use of surveillance techniques enabled by FISA Section 702, which national security officials use to monitor emails and phone calls of certain foreign nationals outside of the US.

The violations identified by the surveillance court concern improper searches for information on Americans the FBI made of the database composed of intelligence collected through 702 surveillance. While FISA 702 surveillance is aimed only at foreign nationals, the names and communications of American citizens are often swept up in the intercepted content, prompting concerns from civil liberty advocates.

According to the October 2018 ruling from Foreign Intelligence Surveillance Court Judge James E. Boasberg, the problematic searches made by the FBI were not likely to return foreign intelligence information or evidence of a crime -- the statutory requirements for the use of the database by the FBI.

Some of the searches appear to be connected to FBI personnel or contractors, as well as people who cooperated with FBI investigators, which could suggest some in the FBI were using the data to vet people they did work with.

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