(CNN) Multiple witnesses who interviewed with the Justice Department Inspector General's Office as part of its probe into the opening of the Russia investigation have been asked in recent days to come in and review portions of the draft report, a sign that the highly anticipated document is nearing publication, people familiar with the situation told CNN.

The report, which is said to scrutinize the FBI's use of surveillance techniques against a Trump campaign adviser, is expected to be released with minimal redactions, and could land among the unfolding impeachment proceedings as a boon for Republicans who've accused law enforcement of abusing its power as it investigated President Donald Trump.

Investigators from the watchdog office reviewed more than 1 million records and conducted more than 100 interviews as part of the review, and in recent weeks, the Justice Department and FBI have pored over a draft of the report to determine the classification levels of the material, Inspector General Michael Horowitz has told lawmakers.

Inspectors general will usually offer witnesses an opportunity to review sections of the report that concern them, and offer comments, as a final step before completing a report. Witnesses in this case have set up times for such reviews over the next two weeks, the people familiar with the situation said, meaning the report could be released in the days before or after Thanksgiving.

The Associated Press first reported that witnesses were being contacted to review the draft report. A spokeswoman for Horowitz declined to comment, as did a spokeswoman for the Justice Department.

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