WASHINGTON » The Internal Revenue Service commissioner will testify before two House committees next week about the agency’s disclosure that it lost thousands of emails sought by investigators looking into accusations of politically motivated misconduct by the agency, the committees said Monday.

The IRS told congressional investigators Friday that two years’ worth of emails sent and received by Lois Lerner, the former official at the center of the inquiry, had been destroyed because of a computer crash in mid-2011. The committees are examining whether the lost emails involved obstruction or a violation of the Federal Records Act, aides to the committees said.

The IRS’ disclosure, included in a filing to the Senate Finance Committee, added to suspicions among Republican lawmakers that the IRS was not cooperating fully with the investigations of its treatment of conservative political groups seeking tax-exempt status during the 2012 campaigns.

"I will not tolerate your continued obstruction and game-playing," Rep. Darrell Issa, R-Calif., the chairman of the Oversight Committee, wrote in a letter to the IRS commissioner, John Koskinen, on Monday after issuing a subpoena for him to appear.

The scandal has divided Republicans and Democrats on the various committees investigating the IRS. An aide to Democrats on the Oversight Committee, who spoke Monday on the condition of anonymity, said that the lost emails had been disclosed previously in IRS documents received by the committee under subpoena, and that Issa was feigning surprise.

Koskinen is scheduled to appear before Issa’s committee on Monday night and, voluntarily, before the Ways and Means Committee on Tuesday. The Ways and Means chairman, Rep. Dave Camp, R-Mich., wrote a letter to President Barack Obama on Monday asking for "all communications between Lois Lerner and any persons with the executive office of the president" for the period between January 2009 and May 2011, when the lost emails were exchanged.

The IRS initially provided 11,000 of her emails that it deemed directly related to the applications for tax exemption filed by political groups. Under pressure from Republican leaders, Koskinen later agreed to provide all of Lerner’s emails but said that doing so might take years. Since then, the IRS has provided roughly 32,000 more emails directly from Lerner’s account.

After the agency discovered that its initial search of Lerner’s emails was incomplete because of the computer crash, it recovered 24,000 of the missing messages from email accounts on the other end of Lerner’s correspondence, the IRS said.

Although Koskinen had indicated in congressional testimony that IRS emails were stored on servers in the agency’s archives and could be recovered, the agency said Friday that was not the case.