Multiple power substations in a North Carolina county were damaged by gunfire in an apparent act of criminal vandalism, leaving tens of thousands of people without electricity, authorities said.

The power outage across Moore County that began just after 7 p.m. Saturday is being investigated as a criminal act, Moore County Sheriff Ronnie Fields said in a Facebook post. More than 40,000 electric customers in the county remained without power on Sunday morning, according to poweroutage.us.

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

Southern Pines Fire Chief Mike Cameron said that two substations in the county were damaged by gunfire on Saturday and that a possible motive wasn’t clear. Cameron, also the assistant town manager, said that the information about the cause was given to him by Duke Energy. A Duke Energy spokesman didn’t immediately respond to an email asking about the gunfire.

Moore County deputies and other law enforcement responded and were providing security at the affected sites, the sheriff’s office said.

Duke Energy spokesman Jeff Brooks said in an earlier statement that the company experienced “multiple equipment failures” at substations and the power company was “investigating signs of potential vandalism related to the outages.”

Duke Energy said power was expected to be restored by Sunday evening.

The Pilot newspaper in Southern Pines reported that one of its journalists saw a gate to one of the substations had been damaged and was lying in an access road.

“A pole holding up the gate had clearly been snapped off where it meets the ground. The substation’s infrastructure was heavily damaged,” the newspaper reported.

The newspaper reported that Moore County Regional Hospital was operating on generator power.

Southern Pines Fire and Rescue reported the town’s water and sewer services are also operating on backup generators. Authorities in the area asked people to stay off the roads if possible or proceed with caution because traffic lights were out of service.

Cameron, the fire chief, said that there have been several accidents at intersections where the traffic lights are out. He said the most significant involved four cars on Saturday night just after the power went out and sent four people to the hospital with minor injuries.

He said that authorities are putting temporary stop signs at some intersections.

North Carolina Gov. Roy Cooper said in a message posted to Twitter that the state was providing resources to investigators and power crews.

“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,” he said.

The county of approximately 100,000 people lies about an hour’s drive southwest of Raleigh and is known for golf resorts in Pinehurst and other communities.