The Nevada state government was forced to cancel all in-person services and shut down its public website after suffering an unspecified "network security incident".
The office of Governor Joe Lombardo said on Monday afternoon that it was working to restore its computer systems and investigate the reason why it had been compromised.
It said that all state offices would be closed to in-person visits throughout Monday, but that emergency call-taking and "essential services" such as 911 remained available.
Affected services included the Nevada DMV, the Public Utilities Commission, the dispatch phone lines of the State Police and Highway Patrol, and various other phone lines and online systems.
The Nevada government's website was still offline as of 9 p.m. local time.
"On early Sunday morning, the State of Nevada identified a network security incident and immediately engaged in 24/7 recovery services. The matter is still under active investigation," Lombardo's office said on X, the social network.
"The state is focused on restoring services safely and validating systems before returning them to normal operation...
"At this time, there is no evidence that any personally identifiable information was compromised."
The office added that Nevadans should be wary of "unsolicited calls, emails, or texts" exploiting the situation by asking for "personal information or payments."
Nothing more was revealed about the cause of the incident, including whether it was malicious and who or what may have been responsible.
In a prior statement on Sunday, the Governor's Technology Office said the incident had started around 1:52 a.m. on Sunday and that some services might be "hard to reach or briefly down".
If that happens, the Office advised, users should try again later.
The U.S. Cybersecurity and Infrastructure Security Agency said it was "actively tracking this network security incident" and "collaborating with the State of Nevada to offer assistance."
The FBI's Las Vegas field office also confirmed that it was helping with the investigation.
