WASHINGTON — Lois Lerner, head of the Internal Revenue Service division on tax-exempt organizations, was put on administrative leave Thursday, a day after she invoked the Fifth Amendment and declined to testify before a House committee investigating the unit’s targeting of conservative groups.

Lawmakers from both parties said Thursday that senior IRS officials had requested Lerner’s resignation but she refused, forcing them to put her on leave instead. Whether her suspension will lead to dismissal was unclear, given civil-service rules that govern federal employment.

“The IRS owes it to taxpayers to resolve her situation quickly,” said Sen. Chuck Grassley, R-Iowa. “She shouldn’t be in limbo indefinitely on the taxpayers’ dime.”

An IRS spokeswoman said the agency could not comment on Lerner’s status because it was a personnel matter.

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The move to put Lerner on leave became public minutes after Sens. Carl Levin, D-Mich., and John McCain, R-Ariz., released a letter to the new acting IRS commissioner, Daniel Werfel, demanding Lerner’s immediate suspension for what they said was her failure to disclose information to their Senate Permanent Subcommittee on Investigations.

Werfel confirmed Lerner’s status in an email to employees Thursday and said he had selected Ken Corbin, a deputy director from another IRS division, to fill her job.

Corbin is a deputy director in the wage and investment division, where he oversees 17,000 workers responsible for processing 172 million individual and business tax returns, Werfel said.

If Lerner is dismissed, she would be the third senior IRS official to lose their job in the targeting scandal. The service’s acting commissioner, Steven Miller, was ousted this month, and Lerner’s supervisor, Joseph Grant, director of the tax-exempt and government-entities division, said he would retire June 3.

Lerner has been under severe pressure since May 10, when she delivered an awkward apology to tea-party and other conservative groups whose applications for 501(c)(4) tax exemptions had been singled out for special scrutiny. At that time she said she had learned of the targeting in 2012, when tea-party groups publicly accused the IRS of mistreatment.

But a Treasury inspector general’s audit released days later appeared to make it clear she knew of the effort well before then and had tried to reshape it. Lawmakers from both parties publicly accused her of lying to them.

In her appearance before the House Oversight and Government Affairs Committee on Wednesday, Lerner invoked her constitutional right against self-incrimination and declined to testify.

But the committee’s chairman, Rep. Darrell Issa, R-Calif., said that because she had given an opening statement before invoking the Fifth, she had effectively lost that right. He said he was considering calling her back before his committee.

In her opening statement, Lerner told the committee she had not lied to Congress and had done nothing wrong. Lerner, 62, is an attorney who joined the IRS in 2001. Her 34-year career in federal government has included work at the Justice Department and Federal Election Commission.

At the IRS, she oversaw 900 workers and a budget approaching $100 million.

Material from The Washington Post and The Associated Press is included in this report.