Attorney General William Barr is reportedly threatening to pull out of a hearing before the House Judiciary Committee this week.

A committee source told CNN that Barr objects to the format planned for Thursday's hearing, which is focused on special counsel Robert Mueller's investigation into Russian interference in the 2016 election.

Chairman Jerrold Nadler, D-N.Y., wants two rounds of questions, one for members and a second in which each counsel for the Democratic Party and Republican Party would have the opportunity to ask questions. He also proposed a closed session to discuss redacted sections in Mueller's report.

Barr objects to the added sessions and the closed session. The Justice Department has signaled that Barr may not show up unless Nadler backs off.

"Discussions are still ongoing, to be picked back up tomorrow," a Justice Department official told the Washington Examiner. "Our position is that it’s a congressional hearing, therefore members do the questioning."

Nadler told CNN that Barr would not "dictate the format of the Judiciary Committee."

Barr is also scheduled to appear before the Senate Judiciary Committee on Wednesday, which is still expected to happen.