AUSTIN, Texas (AP) — Former Texas congressman Ron Paul is apologizing for an "offensive cartoon" with racist illustrations that he says a staff member inadvertently posted to his social media.

A tweet Monday featured four men drawn in racist stereotypes punching Uncle Sam while yelling "Cultural Marxism!" The cartoon was removed following swift backlash on social media.

The 82-year-old Paul ran for president three times and retired from Congress in 2012. He signed his name to a tweet saying he doesn't make his own social media posts and that the cartoon was removed "when I discovered the mistake."

While running for the GOP presidential nomination in 2012, Paul also disowned racist and homophobic screeds in newsletters he published decades ago.