While special counsel Robert Mueller has already made the scope of his testimony publicly clear, the Justice Department officially instructed the special counsel to not speak about the Russia probe beyond what is in his report.

Associate Deputy Attorney General Bradley Weinsheimer told Mueller in a letter Monday that his testimony before two House committees on Wednesday should “remain within the boundaries of your public report because matters within the scope of your investigation were covered by executive privilege,” the letter said.

“These privileges would include discussion about investigative steps or decisions made during your investigation not otherwise described in the public version of your report,” it said.

Democrats are expected to press Mueller to expand on examples of Trump’s behavior, including apparent attempts to obstruct justice.

Read the letter from Weinsheimer below: