WASHINGTON -- A new report by Justice Department investigators has identified dozens of recent cases in which department employees have been accused of serious violations of civil rights and civil liberties involving enforcement of the federal anti-terrorism law known as the Patriot Act.

The inspector general's report was presented to Congress last week and is awaiting public release.

The report said that during the six-month period that ended June 15, the Inspector General's Office received 34 credible complaints of civil rights and civil liberties violations by department employees, including accusations of beatings of Muslim and Arab immigrants in federal detention centers.

The accused workers are employed in several of the agencies that make up the Justice Department, with most of them assigned to the Bureau of Prisons.

A Justice Department spokeswoman said Sunday that the department "takes its obligations very seriously to protect civil rights and civil liberties, and the small number of credible allegations will be thoroughly investigated."

She noted that the department was continuing to review accusations made last month in a separate report by the inspector general that found broader problems in the department's treatment of hundreds of illegal immigrants rounded up after the Sept. 11 terrorist attacks.

While most of the accusations in the new report are still under investigation, the report said a handful of others had been substantiated, including those against a federal prison doctor who was reprimanded after reportedly telling an inmate during a physical examination that "if I was in charge, I would execute every one of you" because of "the crimes you all did."

The report did not otherwise identify the doctor, who received a verbal reprimand from his superiors.