WASHINGTON (AP) — The FBI is failing to report all suspected child sexual abuse cases to appropriate law enforcement agencies, according to a Justice Department watchdog report released Thursday. The review found no evidence that the FBI complied with mandatory reporting requirements in about 50 percent of the cases examined by the inspector general.

The inquiry found failures in how the FBI is responding to the allegations in some cases even after improvements prompted by its handling of the case against former USA Gymnastics team doctor Larry Nassar.

In a review of 327 cases involving allegations of sex crimes against children, the inspector general found no evidence that that suspected child abuse was reported to appropriate local law enforcement agencies in 47 percent of the cases. When were reports were made, they were made within the 24-hour period, as is required by Justice Department policy, in only 43 percent of the cases.

A senior FBI official acknowledged that the bureau has made mistakes in investigating crimes against children but said the "vast majority of work" has been handled appropriately.

The official, who briefed reporters on condition of anonymity under ground rules set by the FBI, said the bureau has put in place policies and processes to continue to improve because "this is a no-fail mission."

"Ensuring the safety and security of children is not just a priority for the FBI; it is a solemn duty that we are committed to fulfilling with the highest standards. The FBI's efforts combating crimes against children are among the most critical and demanding undertakings we do," the FBI said in a statement.

The report follows a Justice Department inspector general inquiry into the FBI's handling of sexual abuse allegations against Nassar. That inquiry found that the FBI's failure to promptly investigate the allegations against Nassar allowed the doctor to continue to prey on victims for months before his 2016 arrest.