Armed robbers burst into a Dartmouth, N.S., house Saturday night and attacked two people inside.

Police say the home invaders covered their faces and one brandished a gun. They knocked on a door on Glen Manor Drive near Mic Mac Mall at 10:15 p.m.

The man who opened the door was knocked down and he and a woman living in the house were tied up. Sgt. Rob Lowther of the Halifax Regional Police says the robbers took several items and fled on foot.

"There was another resident, a neighbour, who had witnessed obviously suspicious activity: a man with a mask carrying a handgun. She called 911. While police were responding, the initial victims, who were tied up, managed to free themselves and call 911," he said.

Police blocked several blocks of the neighbourhood and sent in the canine unit, but the dogs found nothing. Lowther says the robbers may have escaped in a vehicle.

Lowther added that the masked men had been seenĀ outside a different home earlier, leading police to investigate the possibility the attack was random. No one has been arrested.