The craze is similar to the "happy slapping" trend in Britain a number of years ago.
Although the number of physical assaults in New York rose, general antisemitic incidents including graffiti and harassment, fell across the city, and the United States, last year.
Evan Bernstein, the ADL's New York regional director, said: “What we have seen in the past is that when things happen in Israel, for example, it could stir things up here. But that wasn’t the case last year.
"The rise of assaults in certain areas of New York City - in particular Brooklyn - is both disturbing and a sobering reminder that antisemitism is not just history but remains a current event.”
One incident involved a 12-year-old girl being punched in the head, and in another a Jewish pensioner was punched in the face.
