The Department of Justice (DoJ) has informed the powerful House of Representatives judiciary committee that the attorney general, William Barr, may not attend a Thursday hearing to review special counsel Robert Mueller’s report of the Trump-Russia investigation.

Barr has expressed objections over the panel’s questioning format, according to a senior Democratic committee aide.

The department has balked at the panel’s plans to allow committee counsels from both sides to question Barr after the traditional round of questioning by members of Congress who sit on the committee, which is currently chaired by the Democrats because they control the House.

Justice officials also told the committee they opposed committee chairman Jerry Nadler’s plan to go into closed session if members want to discuss redacted portions of Mueller’s report.

That’s also according to the aide, who requested anonymity to discuss the confidential communications with the justice department.

Barr is scheduled to testify on Wednesday before the Senate judiciary committee, which is chaired by the Republicans, the party in control of the Senate, and to the House panel on Thursday.

The redacted Mueller report was made public just over a week ago. While it concluded there was not enough evidence to charge members of the Trump campaign with criminal conspiracy between the organisation and Russia, it also determined there was a lot of contact, and that Russia conclusively interfered in the 2016 election. Democrats the following day issued a subpoena for the un-redacted version.

The report also found that it could not exonerate the president on the question of obstruction of justice and if Mueller could he would have done so, while also stating the investigation would not reach a conclusion on whether there had been criminal obstruction. The DoJ has deemed that a sitting president cannot be indicted.

Congress is now conducting further inquiries and a number of other criminal investigations are ongoing, including by federal prosecutors in New York, against the president, though the nature of most of the investigations has not been made public.

• This article was amended on 29 April 2019, to reflect that the Mueller report concluded there was not sufficient evidence to bring charges of criminal conspiracy between the Trump campaign and Russia, and that the investigation would not reach a conclusion on whether there had been criminal obstruction.