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A House hearing on the IRS targeting scandal rapidly broke down into a heated and deeply personal argument between a top Democrat and Republican, moments after former IRS official Lois Lerner once again invoked her Fifth Amendment right not to testify.

Lerner, who last year refused to answer questions about her role in singling out Tea Party and other conservative groups for extra scrutiny when they applied for tax-exempt status, was called back before the House Oversight and Government Reform Committee on Wednesday. Though Republicans argue she waived her Fifth Amendment right by giving a statement during the last hearing, Lerner continued to invoke that right on Wednesday.

"On the advice of my counsel, I respectfully exercise my Fifth Amendment right and decline to answer that question," she said in response to several questions.

But ranking Democratic Rep. Elijah Cummings, D-Md., got into a heated argument with Chairman Darrell Issa, R-Calif., after Issa tried to adjourn the hearing.

Issa at first stood up and prepared to leave as Cummings said he wanted to ask a "procedural question." In seconds, tensions flared.

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    "Mr. Chairman, you cannot run a committee like this," Cummings appealed.

    Cummings' microphone was then turned off, and then flipped back on again. Issa sat down momentarily, but then abruptly told Lerner she was "released" and said: "We're adjourned, close it down."

    Cummings, his microphone again turned off, continued to shout, complaining about the Republicans' "one-sided investigation."

    "I am a member of the Congress of the United States. I am tired of this," he shouted.

    The clash bared long-running tensions between the Democratic and GOP members of the committee over the IRS probe.

    Lerner headed the IRS division that improperly targeted Tea Party and other conservative groups. After publicly disclosing the targeting, Lerner refused to answer questions about it at a congressional hearing last year. Lerner then resigned from her post as the agency’s director of tax-exempt organizations.

    Issa and Lerner’s attorneys have argued about whether she is now still protected from having to testify under the Fifth Amendment. Emails obtained by Fox News revealed an attorney for Lerner negotiated over whether she would testify.

    Issa claimed Wednesday that Lerner's testimony remains critical.

    "Ms. Lerner is uniquely positioned to provide testimony that will help the committee better understand how and why the IRS targeted conservative groups," he said.

    Issa warned that the committee may consider whether to hold her in contempt if she continues to stay silent. House Speaker John Boehner later made the same threat.

    Last week, Lerner lawyer William Taylor made public a letter in which he told the committee that Lerner would testify on Capitol Hill only if compelled by a federal court or if given immunity for the testimony.

    He was responding to a letter from Issa saying, in part, that Lerner’s testimony remains "critical to the committee’s investigation."

    The Associated Press contributed to this report.