Washington ? Mortgage-market giant Freddie Mac announced Monday that it had fired its president because he didn’t cooperate with an internal review of the firm’s accounting, now being investigated by federal regulators.

The company said it had dismissed the president and chief operating officer, David Glenn, and that chairman and chief executive Leland Brendsel had resigned. Vaughn Clarke, the company’s executive vice president and chief financial officer, also resigned.

The federal agency that oversees Freddie Mac, the Office of Federal Housing Enterprise Oversight, is investigating the company’s accounting.

In a letter to the company, agency Director Armando Falcon said he had “become increasingly concerned about evidence that has come to light of weakness in controls and personnel expertise in accounting areas and the disclosure of misconduct on the part of Freddie Mac employees.”

Freddie Mac said it had dismissed Glenn “because of serious questions as to the timeliness and completeness of his cooperation and candor” with attorneys engaged in January by the board of directors’ audit committee to review the accounting problems.

The company doesn’t believe that fraud or criminal misconduct were involved, Freddie Mac’s new chief executive officer and president, Gregory Parseghian, told shareholders, financial analysts and reporters in a conference call.

Earlier this year, Federal Reserve Chairman Alan Greenspan expressed concern that Freddie Mac and its larger sister in the home mortgage market, Fannie Mae, may not have adequate capital and that many investors have the misperception that they are backed by the government.

Freddie Mac and Fannie Mae were created by Congress to buy home loans from banks and other lenders to supply ready cash.

Freddie Mac shares dropped 16 percent, or $9.61, to close at $50.26 on the New York Stock Exchange.