Duke Energy Corp said 45,000 customers who lost power in the attack in Moore County five days earlier had electric service restored.

North Carolina Governor Roy Cooper said on Wednesday state authorities and the company were offering monetary rewards of up to $75,000 for information that may lead to the arrest and conviction of those responsible for the attack.

On Saturday night, utility workers investigating reports of widespread outages found broken gates and evidence of gunfire damage to equipment at two substations in the central part of the state.

The area is popular with tourists and known for golf resorts including Pinehurst, which has hosted the U.S. Open and Ryder Cup tournaments.

Schools across the county of 100,000 people canceled classes for students for the forth day on Thursday. A decision on whether to reopen them Friday will be made later.

School officials were worked to ensure that electrical, HVAC and communications were operational before resuming classes, they told local media.

A curfew was imposed earlier amid freezing nighttime temperatures.

Federal law enforcement officials were helping an investigation into the situation, which was also monitored by the White House.

(Reporting by Brendan O'Brien in Chicago; Editing by Chizu Nomiyama)