An ethics watchdog group filed a complaint against Attorney General Jeff Sessions on Friday alleging that his participation in the firing of FBI Director James B. Comey violated Justice Department rules and Sessions’s promise to recuse himself from matters involving Russia.

“Firing the lead investigator is the most extreme form of interfering with an investigation,” wrote Fred Wertheimer, who signed the six-page complaint on behalf of his organization, Democracy 21.

The filing asked the Justice Department’s Office of Professional Responsibility to investigate the matter and issue a public report — and to take additional action.

“Immediately, we call on OPR to take all necessary steps to ensure that the Attorney General withdraws from any participation in the selection of an interim or permanent Director of the FBI,” the complaint said.

When President Trump fired Comey on Tuesday, he announced that he had consulted with Sessions and the department’s No. 2 official, Deputy Attorney General Rod J. Rosenstein.

Wertheimer, who has worked on ethics issues since the Watergate scandal, said the attorney general’s participation in the Comey firing violated Justice Department rules requiring staffers to recuse themselves from any criminal inquiry in which they have a “personal or political relationship.”

He pointed out that Sessions is a potential subject of a Russia inquiry since he met with the Russian ambassador in 2016. In addition, the complaint notes that during his Senate confirmation hearings Sessions agreed to recuse himself from “any investigations into Hillary Clinton’s emails.”

The Justice Department did not respond to a request for comment on the complaint Friday. Filing such a grievance with the Office of Professional Responsibility does not guarantee that the department will respond. In late February, Democracy 21 filed a complaint stating that the attorney general was failing to meet department recusal standards by not announcing he would not participate in campaign-related inquiries.

Two days after that Feb. 27 filing, the attorney general issued a statement announcing that he would recuse himself from “any matters arising from the campaign for President of the United States. “

Until his dismissal this week, Comey oversaw the FBI inquiry into Russian interference in the 2016 election and whether there was any coordination between Russian actors and the Trump campaign or associates.

Separately, Democracy 21 sent a letter to Rosenstein urging him “to appoint a Special Counsel to oversee the Russia investigation” and to take steps to ensure that Sessions plays no role in selecting Comey’s successors.