WASHINGTON, July 22 (Xinhua) -- The U.S. Department of Justice (DOJ) told former special counsel Robert Mueller on Monday to limit his congressional testimony to the public version of his report concluding the Russia probe.

"Any testimony must remain within the boundaries of your public report because matters within the scope of your investigation were covered by executive privilege, including information protected by law enforcement, deliberative process, attorney work product, and presidential communications privileges," according to a letter written by a DOJ official to Mueller.

"These privileges would include discussion about investigative steps or decisions made during your investigation not otherwise described in the public version of your report," said Associate Deputy Attorney General Bradley Weinsheimer.

It is expected that Mueller is unlikely to speak beyond a redacted version of his 448-page report on alleged Russian interference in the 2016 U.S. presidential election and possible obstruction of justice by President Donald Trump.

Weinsheimer said that he was responding to a July 10 letter from Mueller for guidance "concerning privilege or other legal bars applicable to potential testimony in connection" with subpoenas issued by the House Judiciary and Intelligence committees for his appearance.

The associate deputy attorney general reiterated that it is ultimately Mueller's decision to testify, while warning the former special counsel against revealing anything related to the redacted portions of his report.

Mueller is slated to testify in back-to-back hearings about the Russia probe and his final report before two House committees on Wednesday. The two hearings are expected to last roughly five hours combined.

Mueller's report said that there was no evidence that Trump's campaign conspired with the Russian government during the 2016 election, but did not conclude if the president had obstructed justice.

Instead, Mueller recounted 10 episodes involving Trump and discussed potential legal theories for connecting these actions with elements of an obstruction offense.

It was the DOJ that concluded that Mueller did not have "sufficient" evidence to support a charge in the obstruction case. The decision drew scrutiny from Democrats, who called for more investigations.

Mueller indicated he did not want to testify before Congress during a press conference in May, adding that his testimony would not go beyond his report. Nevertheless, his words failed to discourage Democrats from subpoenaing him to testify.

Trump said on Monday that he will not be watching Mueller testify, denouncing Democrats for "wasting their time."

Earlier in the day, he renewed his attacks on Mueller and the Russia probe.