The two groups have been embroiled in a war of words online in recent months, but Sykes is convinced some fans have been taking the rivalry too far.
The singer recently underwent throat surgery and he reveals he was bombarded with vicious messages from One Direction fans around the time of his operation.
He tells Britain's The Sun, "What's surprising is I get death threats and I keep out of it. When I was having my throat surgery, I got tweets saying, 'Hope the surgeon slits your throat while he's at it.'"
Max George insists he has received online threats too, adding, "I'm not from the most pleasant of areas, but I can't remember talking like some of those kids do. Some of them are 10 year olds that know ways of sadistic murder."