US Democratic presidential hopeful Hillary Clinton says a tweet from rival Donald Trump featuring a six-pointed star was "blatantly anti-Semitic".
The tweet included a shape resembling the Star of David and stacks of money, with text describing Mrs Clinton as "Most corrupt candidate ever!"
It was later deleted then reposted with the slogan contained in a circle.
Mr Trump said the media was "dishonest" for comparing it to the Star of David, a symbol of Judaism.
The Mic website reported the image had first appeared on a message board known for anti-Semitism and white supremacy.
"Donald Trump's use of a blatantly anti-Semitic image from racist websites to promote his campaign would be disturbing enough," Mrs Clinton's campaign team told US media.
"But the fact that it's part of a pattern should give voters major cause for concern."
'Often used by sheriffs'
Mr Trump hit back in a statement, saying it was a "basic star, often used by sheriffs", and that accusations of anti-Semitism were "ridiculous".
He accused Mrs Clinton of trying to deflect attention from her husband's meeting with the US attorney-general.
Dan Scavino, Trump's social media director denied that the image had been lifted from an anti-Semitic site and said it was taken from "an anti-Hillary Twitter user where countless images appear".
Mr Scavino defended himself against the ant-Semitic claims in a tweet on Tuesday.
"For the MSM to suggest that I am antisemite is AWFUL. I proudly celebrate holidays w/my wife's amazing Jewish family for the past 16 years," he wrote, using an abbreviation for mainstream media.
The Star of David features on the Israeli flag, and was used by the Nazis to identify Jews.
Mr Trump has previously come under scrutiny for reposting comments made by supremacist groups on social media.
Earlier this year, he was criticised on his failure to immediately disavow David Duke, a leader of the white supremacist Ku Klux Klan, who had endorsed him.