Two people airlifted to hospital, two more have minor wounds, and 37 dogs and several cats seized.
Four people have been injured, two badly, following a dog attack.
North Wales Police went to an address on the LlÅ·n peninsula in Gwynedd on Friday morning, after reports of a dangerous dog.
Two people were airlifted to hospital with serious injuries, and another two had minor injuries.
The dog involved was destroyed, and is yet to be examined to establish the breed. A total of 37 dogs and a number of cats were seized from the address.
Councillor Gareth Williams said the attack was in Rhydlios: “As a community, there’s a sense of shock and concern at the news.
“My biggest concern is the fact that there is a public footpath not far from the house, and also families that live in close proximity.”
He said that “our thoughts are with everyone concerned” and hoped that they all make a quick recovery.
Police remained in the area on Saturday while inquiries continue.
Ch Supt Sian Beck said: ” We understand this was a concerning incident in the local, and wish to reassure the community that there is no further risk to the wider public.
“We have launched a joint investigation with the RSPCA.”
The force are appealing for anyone with any information.