WASHINGTON (AP) -- The new acting head of the Internal Revenue Service is telling Congress that American taxpayers no longer trust the agency amid a growing number of scandals -- from targeting conservative political groups to lavish spending on employee conferences.

But acting IRS Commissioner Danny Werfel says he is "committed to restoring that trust." Werfel says he has installed new leadership at the agency and is conducting a thorough review of what went wrong and how to fix it.

Werfel was testifying Monday before a House Appropriations subcommittee in his first public appearance since taking over the agency nearly two weeks ago.

The IRS has acknowledged that agents improperly targeted conservative political groups for additional scrutiny when they applied for tax-exempt status during the 2010 and 2012 elections.