IRS officials who targeted Tea Party groups for extra audits during the last election cycle can expect the House Oversight and Government Reform Committee to “aggressively” crack down on the activity, Republican leaders said Friday.

“The fact that Americans were targeted by the IRS because of their political beliefs is unconscionable,” chairman Darrell Issa, R-Calif., and subcommittee Chairman Jim Jordan, R-Ohio, said in a statement. “The Committee will aggressively follow up on the IG report and hold responsible officials accountable for this political retaliation.”

IRS’s Lois Lerner admitted Friday that “low-level” employees in Cincinnati who flagged nonprofit groups for extra review if their name contained the term “tea party” or “patriot.”

“The IRS would like to apologize for that,” Lerner said. She issued the apology in advance of an inspector general report on the IRS’ practices with respect to Tea Partiers, an investigation prompted by Issa, Jordan, Senate Minority Leader Mitch McConnell, R-Ky., and other lawmakers following complaints from Tea Party activists.

Lerner’s apology did not satisfy grass-roots activists or Republican leaders. “President Obama must also apologize for his administration ignoring repeated complaints by these broad grassroots organizations of harassment by the IRS in 2012, and make concrete and transparent steps today to ensure this never happens again,” said Jenny Beth Martin of the Tea Party Patriots.

McConnell suggested that Obama intervene. “Today, I call on the White House to conduct a transparent, government-wide review aimed at assuring the American people that these thuggish practices are not underway at the IRS or elsewhere in the administration against anyone, regardless of their political views,” McConnell said in a statement. “Now more than ever we need to send a clear message to the Obama Administration that the First Amendment is non-negotiable, and that apologies after an election year are not an sufficient response to what we now know took place at the IRS. This kind of political thuggery has absolutely no place in our politics.”