By Tim Reid

Washington, Jan 31 (Reuters) - Aides to Elon Musk Charged With Running the U.S. Government Human Resources Agency Have Locked Career Civil Servants Out of Computer Systems That Contain the Personal Data of Millions of Federal Employees, According to Two Agency Officials.

Since Taking Office 11 Days Ago, President Donald Trump Has Embarked on a Massive Government Makeover, Firing and Sidelining Hundreds of Civil Servants in His First Steps Toward Downsizing the Bureaucracy and Installing More Loyalists.

Musk, the Billionaire Tesla Tsla.o CEO and X Owner Tasked by Trump to Slash the Size of the 2.2 Million-Strong Civilian Government Workforce, Has Moved Swiftly to Install Allies at the Agency Known as the Office of Personnel Management.

The Two Officials, Who Spoke to Reuters on Condition of Anonymity for Fear of Retaliation, Said Some Senior Career Employees at Opm Have Had Their Access Revoked to Some of the Department's Data Systems.

The Systems Include a Vast Database Called Enterprise Human Resources Integration, Which Contains Dates of Birth, Social Security Numbers, Appraisals, Home Addresses, Pay Grades and Length of Service of Government Workers, the Officials Said.

"We Have No Visibility Into What They Are Doing With the Computer and Data Systems," One of the Officials Said. "That Is Creating Great Concern. There Is No Oversight. It Creates Real Cybersecurity and Hacking Implications."

Officials Affected by the Move Can Still Log on and Access Functions Such as Email but Can No Longer See the Massive Datasets That Cover Every Facet of the Federal Workforce.

Musk, Opm, Representatives of the New Team, and the White House Did Not Immediately Respond to Requests for Comment.

Opm Has Sent Out Memos That Eschew the Normal Dry Wording of Government Missives as It Encourages Civil Servants to Consider Buyout Offers to Quit and Take a Vacation to a "Dream Destination."

Don Moynihan, a Professor at the Ford School of Public Policy at the University of Michigan, Said the Actions Inside Opm Raised Concerns About Congressional Oversight at the Agency and How Trump and Musk View the Federal Bureaucracy.

"This Makes It Much Harder for Anyone Outside Musk's Inner Circle at Opm to Know What's Going on," Moynihan Said.

Musk Influence

A Team Including Current and Former Employees of Musk Assumed Command of Opm on Jan. 20, the Day Trump Took Office. They Have Moved Sofa Beds Onto the Fifth Floor of the Agency's Headquarters, Which Contains the Director's Office and Can Only Be Accessed With a Security Badge or a Security Escort, One of the Opm Employees Said.

The Sofa Beds Have Been Installed so the Team Can Work Around the Clock, the Employee Said.

Musk, a Major Donor to a Famously Demanding Boss, Installed Beds at X for Employees to Enable Them to Work Longer When in 2022 He Took Over the Social Media Platform, Formerly Known as Twitter.

"It Feels Like a Hostile Takeover," the Employee Said.

The New Appointees in Charge of Opm Have Moved the Agency's Chief Management Officer, Katie Malague, Out of Her Office and to a New Office on a Different Floor, the Officials Said.

Malague Did Not Respond to a Request for Comment.

David Lebryk, the Top-Ranking Career U.S. Treasury Department Official, Is Set to Leave His Post Following a Clash With Allies of Musk After They Asked for Access to Payment Systems, the Washington Post Reported on Friday.

The New Team at Opm Includes Software Engineers and Brian Bjelde, Who Joined Musk's Spacex Venture in 2003 as an Avionics Engineer Before Rising to Become the Company's Vice President of Human Resources. Bjelde's Role at Opm Is That of a Senior Adviser.

The Acting Head of Opm, Charles Ezell, Has Been Sending Memos to the Entire Government Workforce Since Trump Took Office, Including Tuesday's Offering Federal Employees the Chance to Quit With Eight Months Pay.

"No-One Here Knew That the Memos Were Coming Out. We Are Finding Out About These Memos the Same Time as the Rest of the World," One of the Officials Said.

Among the Group That Now Runs Opm Is Amanda Scales, a Former Musk Employee, Who Is Now Opm's Chief of Staff. in Some Memos Sent Out on Jan. 20 and Jan. 21 by Ezell, Including One Directing Agencies to Identify Federal Workers on Probationary Periods, Agency Heads Were Asked to Email Scales at Her Opm Email Address.

Another Senior Adviser Is Riccardo Biasini, a Former Engineer at Tesla and Most Recently a Director at the Boring Company, Musk's Tunnel-Building Operation in Las Vegas.

(Reporting by Tim Reid; Editing by Ross Colvin and Howard Goller)

((Timothy.reid@Thomsonreuters.com))