SEABROOK, N.H. – Seabrook nuclear plant officials were put through their paces Friday when a false alarm prompted authorities to search for hours for a possible intruder and detain two men who had approached the plant.

Plant spokesman Alan Griffith said Saturday that the plant’s video surveillance camera and intrusion detection system went off around 9 p.m. Friday and the camera picked up something inside the fence, though not close to the plant itself.

Griffith said authorities searched the plant grounds until 11 a.m. Saturday but found no sign of intruders. He said officials don’t know what triggered the alarm, but thought it might have been an animal brushing against the fence.

“This in no way appears to have been a terrorist-related incident,” plant officials said in a news release.

Officials said that as police were responding to the alarm, they came across and detained two men who were driving on the plant’s north access road. The men apparently had driven to the security guard house and said they were lost.

Police Chief David Currier said guards told the men to head back out the access road to Route 1, but Seabrook police stopped them before they reached Route 1 and questioned them.

The men eventually were released and do not face any charges. Plant officials said Saturday there was no evidence of any connection between the men and the alarm.

Jim Van Dongen of the state emergency management agency said he was notified of an unusual event at the plant shortly before 9 p.m.