A man clambered over a White House fence Sunday afternoon, triggering a brief lockdown until he was apprehended by Secret Service personnel, an official told NBC News. The unidentified man, who climbed the north fence at 3:55 p.m. ET, will likely be transported to the Metropolitan Police Department, the official said. He was arrested on the north lawn. The official said the man was apprehended immediately after he jumped the fence and that the Secret Service responded immediately. It is standard procedure for the White House to go into lockdown mode after such an incident.