One of Donald Trump’s senior foreign policy advisors has apologized for sharing a blatantly anti-Semitic post on Twitter over the weekend.

Retired Lieutenant General Michael Flynn on Sunday responded to the claim made by Hillary Clinton campaign manager Robby Mook that Russian intelligence agencies were behind the Democratic National Committee hack that exposed tens of thousands of staffers’ emails.

“The corrupt Democratic machine will do and say anything to get #NeverHillary into power. This is a new low,” Flynn tweeted, sharing a link to a tweet from user Saint Bibiana who wrote “>Cnn implicated. ‘The USSR is to blame!’ … Not anymore, Jews. Not anymore.”

The user’s tweet linked to a CNN Politics clip of Mook’s comments.

Flynn, who spoke at the Republican National Convention last week, deleted the Tweet and issued an apology hours after posting it, saying it was “a mistake” and that he only meant to share the CNN video.

This is not the first time that the Trump campaign has had to answer for sharing anti-Semitic messages.

Earlier this month, Trump shared a post accusing Clinton of corruption that featured a photo of the Democratic nominee along with piles of cash and a six-pointed star that resembled the Star of David. The campaign insisted the image was not meant to be anti-Semitic and that it was actually a “plain” or “sheriff’s” star, though the user who originally posted it regularly shared other anti-Semitic messages.

Jewish journalists covering the Trump campaign have faced anti-Semitic harassment from his supporters, and he has repeatedly had to disavow the support of David Duke, an avowed anti-Semite and former Grand Wizard of the Ku Klux Klan.