British Prime Minister Rishi Sunak on Friday said that American XL bully dogs would be banned by the end of the year after a man was killed in another suspected attack on Thursday.

The announcement came less than a week after one of the stocky, muscular dogs was involved in an attack on an 11-year-old girl who was walking to the shops with her sister in the English city of Birmingham.

Announcing the plan, Sunak said he “shares the nation’s horror” regarding a series of serious dog attacks.

“It’s clear this is not about a handful of badly trained dogs, it’s a pattern of behaviour and it cannot go on,” Sunak said in a video message.

He said a man was killed on Thursday in central England in an attack involving a suspected XL bully dog. Police said a man had been arrested on suspicion of manslaughter.

According to campaign group Bully Watch, which advocates for a ban on selling and breeding large XL bully dogs, the breed was responsible for more than half of all fatal dog attacks in Britain last year.

XL bully dogs were originally bred from American pit bull terriers and American Staffordshire terriers and first appeared in the UK “around 2014 or 2015”, with the numbers growing rapidly in recent years, the campaign group said.

Sunak has asked the police and experts to define XL bully dogs, a first step he said before he hopes they can be banned by the end of the year.

A number of British animal welfare charities, including the RSPCA, said this week that banning specific dog breeds is not the solution.

In a joint statement, they instead blamed “irresponsible breeding, rearing and ownership” and said the government should instead focus on “dog control regulations, and on promoting responsible dog ownership and training”.