A tweet by pro-Brexit organisation Leave.EU has been branded "offensive" by a cross-party group of MPs.
The All Party Parliamentary Group for British Muslims has called on Leave.EU to withdraw the "inflammatory" post and apologise.
The controversial tweet said: "Is it any wonder that Labour can't be bothered to deal with the disgusting antisemitism in their party when they are so reliant on the votes of Britain's exploding Muslim population? It's a question of maths for these people, not justice!"
Tory MP and co-chairman of the APPG for British Muslims, Anna Soubry, said: "This tweet is thoroughly distasteful and offensive. It is also nothing to do with leaving the EU.
"It is however proof that Leave.EU is a front organisation for a far-right group that is more interested in spreading hatred and creating division than upholding British values of respect and tolerance."
Labour MP Wes Streeting, who is co-chairman of the All Party Parliamentary Group for British Jews, said: "Muslim and Jewish communities will be disgusted by this cynical and nasty attempt to stir up hatred and division.
"Muslims and Jews know what it is to experience prejudice based on their race and religion and will stand together against this type of ugly rhetoric.
"Leave.EU should withdraw this tweet and apologise immediately."