CNN  — 

Authorities have announced a mandatory curfew in a North Carolina county where around 40,000 customers lost power after two power substations were damaged by gunfire Saturday night.

The county will implement a mandatory curfew from 9 p.m. until 5 a.m., starting Sunday night, Moore County Sheriff Ronnie Fields said at a news conference Sunday.

Municipality and county officials “have formed a plan for the night and the next few nights that we may be out of power. It’s a very serious situation,” Fields said. “So we’ve come to an agreement to best protect our citizens and to protect the businesses of our county, we’re going to implement a curfew tonight.”

A state of emergency went into effect at 4 p.m. Sunday as law enforcement, city and energy officials are investigating the incident and working to restore the two substations, authorities said. Law enforcement has also been providing security for the stations, according to the sheriff.

The power outage is being investigated as a “criminal occurrence” after crews found signs of potential vandalism at several locations, CNN previously reported.

Fields said multiple rounds were fired at the two substations. “It was targeted, it wasn’t random,” he said.

No suspects have been identified in connection with the incident. Fields would not say if the criminal activity was domestic terrorism.

“The person, or persons, who did this knew exactly what they were doing,” Fields said. “We don’t have a clue why Moore County.”

Fields acknowledged a woman who posted on Facebook Sunday morning indicating she had been questioned by law enforcement in connection with the incident. Fields did not name the woman, but said she posted false information on social media claiming to have information behind the incident.

“We don’t have anything,” Fields said, when asked about a possible motive. “No motivation, no group has stepped up to acknowledge or accept they’re the ones who [did] it.”

A gate at one of the locations also appears to have been taken off its hinges, Mike Cameron of the Southern Pines Fire and Rescue Department told CNN on Sunday afternoon.

Cameron said the area is experiencing increased emergency calls due to the lack of power, adding that auto accidents have occurred because traffic lights are out. People who rely on oxygen have placed emergency calls, he said.

More than 37,000 customers were without power across the county Sunday evening, according to the Duke Energy outage map. According to poweroutage.us, about 38,000 customers had lost power in Moore County and neighboring Hoke County.

Moore County Manager Wayne Vest said a shelter, running on a generator, opened Sunday afternoon at the Moore County Sports Complex in conjunction with the Red Cross. Vest said additional trailers with bathroom and shower facilities are also being brought to the shelter.

Power restoration could take until Thursday, energy company says

The estimated cost of the substation damage is in the “millions,” the sheriff said.

Restoration to the two substations could take until Thursday for some customers, Jeff Brooks, principal communications manager for Duke Energy, said at Sunday’s news conference.

“We are going to be working around the clock, all hands-on deck, to get power back as quickly and safely as possible,” Brooks said.

Duke Energy will continue to work with the Moore Sheriff’s Office and county officials to support the investigation.

Duke Energy personnel work to restore power at a crippled electrical substation in Carthage, North Carolina.

Brooks said there had been “intentional impact” on the substation damaging multiple pieces of equipment of the substations, causing power to go out. In this instance, rerouting power is not an option, he said.

“Equipment will have to be replaced,” Brooks said. “We are looking at a pretty sophisticated repair with large equipment. This will be a multiday restoration for most customers, extending possibly to Thursday.”

A local supermarket is distributing ice to impacted residents, according to a news release from grocery chain Harris Teeter.

The power outage has also led officials to cancel Monday classes for all schools in the county. “An announcement will be made tomorrow evening to inform parents and staff of the status of schools for Tuesday,” Moore County Schools said in a tweet Sunday afternoon.

FBI has joined the investigation, congressman says

02 nc mass power outage MAP

Several communities across the county began experiencing power outages just after 7 p.m. Saturday, the Moore County Sheriff’s Office said in a Facebook post.

“As utility companies began responding to the different substations, evidence was discovered that indicated that intentional vandalism had occurred at multiple sites,” the office said.

At least two substations were vandalized “with criminal intent,” US Rep. Richard Hudson said Sunday morning in a release.

The North Carolina State Bureau of Investigation and the FBI are responding, according to Hudson. He said the motive remains unknown.

Hudson, whose congressional district includes Moore County, said the Southern Pines Police Department has opened a community center for residents to charge devices.

CNN has reached out to Southern Pines police and the FBI.

During the Sunday news conference, Fields addressed rumors circulating on social media that the attack was an attempt to thwart a local drag show.

Fields said law enforcement is working every angle, but “have not been able to tie anything back to the drag show,” which was scheduled for Saturday night in the nearby town of Southern Pines.

On its website, the Sunrise Theater advertised the “Downtown Divas!” drag show starting at 7 p.m. The power was cut shortly after that time, Fields said.

CNN has reached out to the Sunrise Theater as well as the Southern Pines Police Department. CNN has also reached out to Sandhills Pride, the organization behind Saturday’s drag event.

“This was a terrible act,” North Carolina State Senator Tom McInnis said during the news conference. “And it appears to be an intentional, willful and malicious act, and the perpetrator will be brought to justice and prosecuted to the fullest extent of the law.”

Crews were experiencing “multiple equipment failures” that are affecting substations in Moore County, Duke Energy spokesperson Brooks told CNN affiliate WRAL.

“We are also investigating signs of potential vandalism related to the outages,” Brooks said.

Deputies and officers from other law enforcement agencies responded to the different sites to provide security, according to the sheriff’s office.

Gov. Roy Cooper on Sunday tweeted that state law enforcement would join the investigation.

“I have spoken with Duke Energy and state law enforcement officials about the power outages in Moore County. They are investigating and working to return electricity to those impacted,” Cooper said. “The state is providing support as needed.”

Moore County is in central North Carolina, about 50 miles northwest of Fayetteville.

CNN’s Ralph Ellis and Hannah Sarisohn contributed to this report.