John Koskinen, commisioner of the Internal Revenue Service, denied ordering his staff to destroy thousands of emails sought by congressional investigators in 2014 during an investigation of the tax agency's efforts to target conservative groups.

At a hearing before the House Judiciary Committee Wednesday, Koskinen expressed "regret" for stating incorrectly that he planned to turn over records from Lois Lerner, former head of the IRS' tax-exempt unit, during his testimony before the House Oversight Committee in 2014.

"Some of my testimony later proved mistaken," Koskinen admitted.

Republicans on the judiciary panel slammed Koskinen for presiding over the destruction of backup tapes that housed Lerner's emails.

Rep. Jim Jordan, R-Ohio, highlighted the "coincidence" that occurred when documents that had sat untouched for two years disappeared off the tapes shortly after investigators requested copies.

Koskinen faces potential impeachment at the hands of House conservatives over his handling of the IRS targeting probe, particularly over his pledge to provide emails that had already been erased at the time of his testimony.

Democrats on the committee argued the majority had little evidence to support their articles of impeachment.

Rep. John Conyers, the committee's top Democrat, noted Koskinen had been denied access to transcripts of his 2014 testimony to the Oversight Committee even though the primary accusation against him centered on those statements.