MOORE COUNTY, North Carolina: Local authorities said that two power substations in Moore County, North Carolina, were damaged by gunfire, causing damage that could take days to repair and leaving tens of thousands of people without electricity.

The incidents are being investigated as a criminal act, they added.

The county, with a population of some 100,000 people, is located about an hour's drive southwest of Raleigh.

Just after 7 p.m. on December 3, county officials announced a state of emergency, which included a curfew from 9 p.m. to 5 a.m., as well as the closure of county schools on the same day.

On Twitter, Gov. Roy Cooper wrote, "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."

During a news conference, Moore County Sheriff Ronnie Fields said that authorities have not discovered a motive for the attacks, adding that someone pulled up and "opened fire on the substation, the same thing with the other one."

"No group has stepped up to acknowledge or accept that they are the ones that did it. We are looking at all avenues," he added, noting that the FBI was working with state investigators to determine who was responsible.

According to poweroutage.us., some 36,000 electric customers in the county were without power due to the vandalism.

Duke Energy spokesman Jeff Brooks said multiple pieces of equipment were damaged and will have to be replaced.

"We are looking at a pretty sophisticated repair, with some fairly large equipment, and so we do want citizens of the town to be prepared that this will be a multi-day restoration for most customers," Brooks said.

Local school superintendent Dr. Tim Locklear announced that classes would be canceled on December 5, stating, "As we move forward, we will be taking it day by day in making those decisions."

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.