A dog out on a walk happened upon a live US grenade from World War II and eagerly delivered it to his master, police said Monday, but authorities were able to defuse the explosive before it went off.

The animal found the grenade on the ground, picked it up in its jaws and trotted back to its owner.

A 40-year-old woman had let the dog off its leash near a stream on a walk Sunday on the outskirts of the town of Erkrath in western Germany's Neander Valley.

"She recognised immediately that it was probably an old, rusted hand grenade," police said. "On the orders of the woman, the dog obediently put his find back next to the stream."

She then alerted the authorities who blocked off the area and dispatched a munitions expert who identified the object as a still live American hand grenade from World War II and defused it.

Germany is still littered with unexploded Allied munitions more than six decades after the war, leading frequently to major evacuations when they are discovered in densely populated areas