Updated

On the heels of the deadly mass shooting at the Washington Navy Yard, a forthcoming internal government report is expected to find that Navy facilities are cutting corners on security in order to cut costs -- leading a Republican congressman to decry "serious security flaws" in the system.

The shooter at the Navy Yard was a former Navy reservist who since leaving the military had been working as a defense contractor. Fox News has learned that Navy Secretary Ray Mabus on Tuesday plans to order a review of security at all Navy and Marine installations.

But Rep. Mike Turner, R-Ohio, chairman of a House Armed Services subcommittee, revealed late Monday that a forthcoming inspector general report will address security procedures at Navy installations. Though that report has not yet been released, Fox News confirms that it determines the Navy is not taking enough security precautions when it comes to outside contractors.

The audit was expected to look at the Navy Installations Command, which is part of the Washington Navy Yard, among other locations. The details of the audit were first reported by Time.

Turner wrote to the Department of Defense inspector general on Monday calling for an "immediate briefing" on the findings.

More On This...

    "Given the disturbing events of today, I am highly concerned that the access control systems at our nation's military installations have serious security flaws," he wrote.

    "It is my understanding the IG report indicates the Navy may have implemented an unproven system in order to cut costs. I also learned that potentially numerous felons may have been able to gain unrestricted access to several military installations across the country due to the insufficient background checks, increasing the risk to our military personnel and civilian employees."

    According to an inspector general memo, the audit began in September 2012. Officials were looking at how Navy facilities were "mitigating access control risks to Navy installations."

    Details are still emerging about how and why Aaron Alexis, 34, walked into a single building at the Navy Yard and started shooting, killing 12. Alexis also died.

    It is unclear whether any changes in security protocol made a difference. Time reported that the forthcoming audit shows many felons have gotten unauthorized access and bypassed Navy security.

    Fox News' Chad Pergram and Justin Fishel contributed to this report.