Washington (CNN) When California Republican Rep. Devin Nunes sat before a committee Wednesday to testify on a bill, Democrats tried to use the opportunity to question the House Intelligence Committee chairman on his investigation of Russian meddling and the 2016 presidential race.

But the Republican chairman of the House Rules Committee -- Rep. Pete Sessions of Texas -- allowed Nunes to leave the hearing before Democrats could fire off their questions, prompting criticism from Democrats.

Caroline Boothe, a spokeswoman for the Rules Committee, said the plan beforehand was that Nunes would give his opening statement on the related legislation before the committee -- the Intelligence Authorization Act -- then leave to attend other business, while Rep. Frank LoBiondo, a New Jersey Republican, would step in to take questions from the committee about the bill.

While Boothe initially said Democrats were made aware before the hearing that LoBiondo would be filling in for Nunes during the questioning, she later said that Democrats were not given advance notice.

Sessions, however, at the beginning of the hearing noted that Nunes would be leaving to attend other business.

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