Trump retweeted and then quickly deleted an image of a Nazi flag alongside a photograph of fellow Republican presidential candidate Jeb Bush.
The image, a collage that the real estate mogul retweeted to his over 4.5 million Twitter followers, also featured an image of Bush in a sombrero next to a cactus.
“This was retweeted by Mr. Trump like hundreds of others. He did not see the accompanying image and the retweet has since been deleted,” Trump spokeswoman Hope Hicks told the Washington Post.
Trump recently lost his lead in the Republican race polls to retired neurosurgeon Ben Carson. He has taken heat for his anti-immigrant agenda and several other social media mishaps.
In July, Trump was criticized for tweeting an image of an American flag with his face superimposed over the stars and Nazi soldiers featured in one of its stripes.
In August, he fired one of his Jewish advisers for racist Facebook posts.