The Labour Party is investigating Councillor Ioan Jones who, it is claimed, posted a comparison between Israeli prime minister Benjamin Netanyahu and Adolf Hitler.
During his time as mayor, Mr Jones is also said to have reposted an image online about investment banker Jacob Rothschild, claiming that his family had "financed both sides of every war since Napoleon".
In December last year, the Labour councillor is said to have posted an image on his public Facebook page which shows a picture of Mr Netanyahu underneath an image of Hitler with the tag line "What’s the difference?"
The image also appears to portray the Israeli leader giving a Nazi salute.
The same Facebook image was allegedly shared earlier this year by one of the party’s minority officers, Dorian Bartley, leading to his suspension by Labour bosses.
In April, 2016, while he was deputy mayor, Mr Jones is reported to have shared another article which claimed the "Israel Lobby manufactured the Labour party’s anti-Semitism crisis".
A spokesman for the Labour Party said: "The Labour Party takes all complaints of antisemitism extremely seriously and we are committed to challenging and campaigning against it in all its forms.
"Complaints about antisemitism are fully investigated in line with our rules and procedures and any appropriate disciplinary action is taken.”
Councillor Jones, who represents the Harlescott ward on Shropshire Council was approached for comment but was unavailable.
Jennifer Gerber, director of Labour Friends of Israel, said: "It is a depressing sign of the times that a Labour councillor would think it acceptable to share such anti-Semitic material. Councillor Jones must be thrown out of the party immediately."