The Workers Circle took part in a rally last Wednesday at Boston's City Hall, advertised by a flier declaring that "Boston Jews demand a ceasefire and a stop to genocide."
Many of the protesters wore shirts reading "Jews say ceasefire" and "not in our name."
The appeal was submitted alongside other organizations including CAIR, Jewish Voice for Peace, and The Jerusalem Fund.
Pressure mounts on the pop star to take a stand on Palestinian rights.