More than 150 dogs were rescued from the fire, which broke out at Manchester Dogs' Home in Harpurhey yesterday evening. The the death toll expected to rise further.
A 15-year-old boy has been arrested on suspicion of arson, the BBC reported today.
The number of dogs initially confirmed to have died in the fire was 43, but that figure rose overnight, it said.
Firefighters said the 150 dogs rescued from the fire had been moved to a sister site.
"A number of people, including police officers and staff were quickly on the scene and put their life on the line to help with the rescue effort."
"We are determined to establish exactly how and why this fire started and will be working closely with our partners from the fire service.
Superintendent Marcus Noden of Greater Manchester Fire and Rescue Service (GMFRS), appealed for anyone with information about the fire to come forward - and also urged people to remain calm in the wake of the dogs' deaths.
