WASHINGTON, Oct. 1 (Xinhua) -- The U.S. Federal Bureau of Investigation (FBI) has failed in fully implementing its security measures against espionage from within, said a report on Monday.

    The 41-page report by the Office of Inspector General (IG) of the Justice Department said that FBI had not enforced some internal monitoring procedures to track its employees' suspicious behavior as IG recommended, including creating a central repository to collect and analyze bizarre.

    The report also found that the FBI, partly due to faulty technology, has yet to establish a program to consistently review suspicious employees to create full case files on them.

    "We believe the FBI must be vigilant in attempting to deter and detect the internal penetrations that have occurred in the past and that may occur in the future," said the report.

    The IG started the investigation on FBI internal security following former FBI officer Robert Hanssen was discovered as a spy for a foreign country over two decades.

    However, the report credits the FBI for taking two IG-recommended steps to crack down on internal spies, creating a new unit to detect security penetrations within the agency and installing senior operational posts in its counterespionage section.

    For its part, FBI assistant director John Miller appreciated the IG report for having found the bureau had made significant progress in several areas, and promised to continue to "work with the IG to make additional progress toward implementing these recommendations and in our efforts regarding espionage activities on the whole."