Vandals wielding firearms are suspected of causing a major power outage across a North Carolina county that has plunged tens of thousands of customers into darkness amid freezing temperatures, according to authorities.
Evidence of sabotage was found at two key electrical substations following the massive blackout Saturday night, prompting the Moore County Sheriff's Office to investigate the incident as a "criminal occurrence" and call in the FBI to assist in the probe.
A state of emergency was declared in Moore County on Sunday and a countywide 9 p.m. to 5 a.m. curfew was imposed Sunday night. Moore County Sheriff Ronnie Fields told ABC News that the curfew will be extended to Monday night.
Jeff Brooks, spokesman for Duke Energy, the local public utility, said the two electrical substations were severely damaged in the attacks and much of the equipment will have to be replaced. He said it could be until Thursday when power is completely restored.
At least 35,430 utility customers awoke for the second day Monday without electricity, officials said.
Schools throughout the county have been canceled indefinitely and a shelter was opened Carthage, a central Moore County town, for residents suffering from the disruption, officials said.
The power outages began at about 7 p.m. Saturday and thousands of Duke Energy customers remained without electricity on Sunday after enduring freezing temperatures overnight.
Fields said at a news conference Sunday that the perpetrator or perpetrators of the sabotage "knew exactly what they were doing." He said multiple shots were fired at each of the damaged substations and a gate was rammed open at one of the properties to reach the target.
"We faced something (Saturday) night in Moore County that we've never faced before, but we'll get through it," Fields said. "I can promise to the perpetrators out there, we will find you."
Fields added, "this was targeted. It wasn't random."
No arrests have been announced. Fields declined to comment on a possible motive, but said the investigation has yet to uncover evidence linking the vandalism to a Downtown Divas drag show in Southern Pines that has sparked community protests. The drag show had been scheduled for Saturday night and was disrupted due to the blackout.
Fields told ABC News on Monday that law enforcement throughout the county has been dealing with a number of emergency calls in the last 48 hours, including a few robberies, one at a gun store.
"It’s been a nightmare," Fields said, adding the FBI, Homeland Security, ATF and a number of federal agencies are involved in this investigation.
Fields said this was an intentional act and if someone dies as a result of the blackout the suspect or suspects could face murder charges.
The sheriff called the attacks an "eye-opener" and said he has spoken to North Carolina Gov. Roy Cooper and state senators and representatives about beefing up security around the county's infrastructure.
Kevin Perry, retired director of critical infrastructure protection at Southwest Power Pool in Arkansas, told ABC News most electrical distribution substations across the country may be vulnerable to vandalism or copper theft, but redundancies and backup systems built into power grids prevent widespread blackouts.
"Substations tend to be out in the middle of nowhere, and that means they’re, for the most part, unattended," Perry said. "If you take out enough equipment then you lose the redundancy and when you lose the redundancy you don’t have any way of feeding power to that particular area and that’s when you end up with a regional blackout like this due to sabotage."
He said the evidence law enforcement has shared with the public so far leads him to believe it may have been a targeted attack and not the work of average vandals taking potshots at the substations.
“When you see two substations taken out, resulting in a regional outage like this, you have to start thinking that yes it’s very possible that it was a planned coordinated attack," Perry said. "The implication is that the shooters knew enough about the grid that these two substations if taken out would cause a blackout in the intended area."
He said that while some critical substations boasting 500,000 volts or higher are mandated by the Energy Policy Act of 2005 to have risk assessments conducted on them and if determined necessary could be required to have ballistic walls around them.
"To try to protect every single substation to that level would be enormously cost prohibitive," Perry said, adding that most low-voltage substations like the ones in Moore County are surrounded by chain-link fences and barbed wire outriggers.
Homeland Security Secretary Alejandro Mayorkas was briefed on the power outages and a spokesperson said the department is coordinating with the FBI. The DHS infrastructure security agency CISA is also offering resources to Duke Energy, which is working to restore power.
"DHS will continue to share information with the FBI, and state and local authorities as the investigation unfolds. CISA leadership and regional teams have offered support to Duke Energy as they work to restore service," a DHS spokesperson said Monday.
National Security Council spokesperson John Kirby said Monday the White House is monitoring the incident closely, adding that shoring up infrastructure against external threats is a major priority.
"We're going to obviously let that investigation play out. I think we've heard the president talk about this many times. He's made critical infrastructure security and the resilience of that infrastructure, regardless of whether it's from natural threats or manmade threats, a priority since the very, very beginning," Kirby said. "We still have a long way to go. I think the president will be the first to admit that.
Brooks said utility crews are working "around the clock" to restore power, but said, "we are looking at a pretty sophisticated repair with some fairly large equipment." Several law enforcement agencies in Moore County were providing security as crews worked to repair the damage.
"We do want citizens to be prepared that this will be a multiday restoration for most customers," Brooks said.
MORE: Thousands of Colorado residents without heat after attack on gas serviceMike Cameron, Southern Pines' assistant town manager and fire chief, told the Raleigh News and Observer said several vehicle accidents were being blamed on the power outage, including a multiple car crash that injured several people at an intersection in Southern Pines.
"The car wreck was totally because the stop lights were out," Cameron told the News and Observer.
MORE: Power restored to over 1.3 million customers in Puerto Rico amid massive outageMoore Regional Hospital in Pinehurst, North Carolina, also lost power and was forced to switch to its backup generator, officials said.
Gov. Cooper said in a Twitter post that he has spoken with Duke Energy and state law enforcement officials about the crisis.
"An attack like this on critical infrastructure is a serious, intentional crime and I expect state and federal authorities to thoroughly investigate and bring those responsible to justice," Cooper tweeted.