Sixteen American pit bull terriers were seized today after police raided an illegal dog breeding operation in Co Down.
They were found at a farm building near Dromara in a major new search operation to trace specially trained fighting dogs.
More than 100 animals, including four pit bulls, were seized last week during two separate raids near Katesbridge.
The PSNI confirmed it assisted staff from the Ulster Society for the Prevention of Cruelty to Animals. There were no arrests.
USPCA chief executive Stephen Philpott said: "We found enough equipment and modifications to buildings to suggest those animals were used in organised dog fighting."
The pit bulls, which are expected to be put down, included both adults and pups.
Last Friday around 60 dogs were seized by animal welfare and police officers as they swooped on a suspected training camp for fighting dogs.
The facility was about a mile from a puppy farm which was raided on Thursday night in Katesbridge, where police recovered around 100 dogs.
The puppies were rescued from appalling conditions during a six-hour overnight operation. It has since emerged some of them had never seen daylight.
The original raid was sparked when boxer dogs were spotted feeding from the carcass of a cow.
The USPCA will launch a legal bid to secure ownership of the dogs this week so it can begin attempts to rehouse the animals.