Lois Lerner, the Internal Revenue Service official at the centre of the scandal over the agency's extra scrutiny of conservative groups, has been put on administrative leave after she refused to resign, according to a US politician.

Republican Senator Charles Grassley of Iowa said on Thursday that Daniel Werfel, the new acting IRS commissioner, was the one who asked for Lerner's resignation.

Darrell Issa, the House Oversight and Government Reform chairman, has accused Lerner, who oversaw the tax-exempt division of the IRS,  of providing "false or misleading information" to his committee on four occasions last year.

On Wednesday, Lerner denied she had done anything wrong, but asserted her constitutional right against self-incrimination.

Lerner was the official who first publicly acknowledged the targeting by responding to a planted question about the topic at an American Bar Association conference on May 10. 

'Political targeting'

The admission came before a Treasury Department inspector-general report found that workers in the Cincinnati office used "inappropriate criteria" such as the terms "Tea Party" and "Patriots" to target the applications of conservative groups for intense scrutiny. 

A bipartisan chorus in congress had been calling for her to leave her post. Democratic Senator Carl Levin and Republican Senator John McCain had written to Werfel earlier on Thursday calling for her to be removed.

The move came one day after Lerner refused to answer questions during a House of Representatives panel hearing into why workers in a Cincinnati, Ohio, field office of the IRS in early 2010 began targeting conservative groups for extra scrutiny when they applied for tax exempt status.

"From all accounts so far, the IRS acting commissioner was on solid ground to ask for her resignation," Grassley said in a statement.

He also said that Lerner "should not be in limbo indefinitely on the taxpayers' dime".

Source: Agencies