Judge Aileen Cannon made the decision after Trump's lawyers demanded that the US Department of Justice not be allowed to release the report.
Special prosecutor Jack Smith has conducted several investigations into Donald Trump, including the events of January 6, 2020, when the US Congress was stormed by rioters. But since Trump was re-elected as president, the special prosecutor has chosen to pause the investigative work.
The judge's decision came after Smith said that investigators were finalizing a comprehensive report on the investigation into Trump – and that a first part could be made public on Friday.
An appeals court in Atlanta, Georgia, will now consider whether the report should be made public.
In a parallel court ruling, Trump's request to postpone the announcement of his sentence in the trial concerning so-called hush money was denied.
Trump's lawyers filed an application to delay the process. But an appeals court in New York rejected it on Tuesday.
Judge Juan Merchan will therefore likely announce the sentence on January 10, ten days before Trump is sworn in as president.
