The acting commissioner of the IRS will announce he is stepping down as early as Tuesday, according to four people familiar with the matter who said the departure is driven in part over his distress about the chaos inflicted on the government by billionaire Elon Musk’s U.S. DOGE Service.

Doug O’Donnell, a civil servant who spent several decades at the agency, will depart the administration by the end of the week, said the people, speaking on the condition of anonymity because they were not authorized to discuss the matter publicly. He is expected to be replaced on a temporary basis by Melanie Krause, who has also served in senior positions at the tax agency, the people said. President Trump has nominated Billy Long, a former Republican congressman from Missouri, to run the agency on a more permanent basis, if he is confirmed by the Senate.