A man was bitten and two others left in terror after a pack of Alsatians went on a rampage in Beeston.
Around four security dogs were thought to have escaped from a nearby property after a fence blew down in high winds.
The animals bizarrely ended up relaxing in a Crossfit gym in the aftermath of the violent attack.
Callum Thomas, 31, was on his way to work at a food factory with his mother when he spotted the dogs surrounding a man on Burton Avenue just after 6am.
"As we approached the street we could hear barking and screaming. There was a guy being attacked. We couldn't get close enough to help him, but a car stopped and he managed to get in. The dogs then started coming towards us so we ran into some gardens.
"My mum was terrified. The dogs walked off but they then attacked another guy. He was bitten on the leg, he had his trousers torn and you could see tooth marks."
Callum and the other man were saved by a passing van driver who took them away from the scene.
"It was fortunate that it was so early and there were no children around, as there is a primary school nearby. I was so shocked - my mum broke down and we both had to miss our shifts. I want to thank the van driver who pulled over and saved us."
The dogs were then photographed by staff at Form Leeds, a Crossfit gym in Holbeck, relaxing on cushions inside the building after appearing outside with no sign of an owner. Gym staff contacted the council dog warden who collected the animals, one of which was in poor health.
West Yorkshire Police said:
"At about 6.30am today, police received calls from members of the public reporting a number of German shepherd-type dogs loose in the street in the vicinity of Burton Avenue, Beeston.
"A 50-year-old man had received a bite to the back of his leg for which he went for hospital treatment. Officers identified the owner of the dogs who lives at a nearby address.
"A crime has been recorded in relation to the incident and enquiries are ongoing."