Washington, Nov 16 (IANS): The US Army chief, General Mark Milley, has said that there are "gaps and failures" on the part of the service to report soldiers' criminal activities to the FBI.

Milley told reporters at the Pentagon on Wednesday that around 10 to 20 per cent of the army's total cases are not reported to the civil law enforcement agency, Xinhua news agency reported.

"The percentage is too high," he admitted while suggesting that "it is a problem across all the services".

Milley's statement came after the Air Force acknowledged last week that it had failed to submit to the Federal Bureau of Investigation (FBI) the assault conviction of former Airman Devin Kelley, who opened fire at a church in Texas and killed 26 people earlier this month.

"We have a significant amount of omissions," Milley said, adding "it clearly tells us that we need to tighten up".

Following the Texas church shooting, Defense Secretary Jim Mattis ordered a review of the handling of criminal records in the Kelley case and relevant procedures of all of the military branches.

"We all know that the situation inside the Air Force that could have been any one of the services," Milley said.

"We need to make sure every one of those is transmitted over to the civilian law enforcement agencies, the FBI for example."

Kelley was convicted of assaulting his then-wife and stepson. He was sentenced to 12 months in prison and received a bad conduct discharge, which was completed in 2014.