WASHINGTON (AP) — President Barack Obama will appoint senior White House budget officer Daniel Werfel to be acting commissioner of the Internal Revenue Service, a White House official says.

Werfel will replace Steven Miller, ousted Wednesday amid revelations that the IRS improperly singled out conservative groups for special scrutiny.

The 42-year-old Werfel is the controller of the Office of Management and Budget, a job akin to a chief financial officer. Though Werfel was appointed to that job by Obama, he also worked during the administration of President George W. Bush.

The official was not authorized to speak on the record about the announcement and revealed Werfel's appointment on the condition of anonymity.

After days of inaction, Obama has tried to move swiftly in response to reports of inappropriate targeting by the IRS.

An administration official says President Barack Obama will name a new acting commissioner of the Internal Revenue Service this week to replace ousted commissioner Steven Miller.

Miller was forced to resign amid revelations that the IRS targeted conservative groups for special scrutiny.

The official would not say who the new commissioner will be. The official was not authorized to be quoted and spoke on condition of anonymity.

Treasury Secretary Jacob Lew sought and received Miller's resignation Wednesday, as the White House tried to contain the controversy over the IRS targeting tea party groups for extra review. The targeting was spelled out in a Treasury inspector general's report and acknowledged by IRS officials.

Obama said Wednesday, quote, "the misconduct that it uncovered is inexcusable."