Two men were being questioned by police last night following the shooting of three people outside a polling station in Draperstown, Co Derry, on Thursday.
Police believe the attack may have been carried out by dissident republicans.
Two of the victims were RUC officers on duty at the polling station in St Mary's Primary School. One was wounded in the shoulder, the other in the arm. The third victim, a 21-year-old woman, was shot in the leg. The shooting took place at about 9.45 p.m., 15 minutes before polling was due to close.
The injured remain in a stable condition in hospital. One of the RUC officers shot once at the gunman, who was using the crowd as cover.
A silver Volkswagen Passat, similar to the car believed to have been used in the attack, was found burned out on Blackwater Bridge outside Drapers town, a short time later.
The RUC Assistant Chief Constable for the area, Mr Sam Kinkaid, said there were between 100 and 150 members of the public queuing to vote in a last-minute rush at the rural polling station. He went on to say: "I believe this attack was carried out by dissident republicans."
The Northern Ireland Secretary, Dr John Reid, said the shooting showed "the total contempt for democracy that these people have".