President Donald Trump shocked many in the nation on Tuesday with a comment that appeared to be a signal to the violent white nationalist organization Proud Boys.

During President Trump’s first presidential debate with Democratic challenger Joe Biden, Trump was pressed by debate moderator, Fox News’ Chris Wallace, to condemn white supremacist groups. Trump ignored the question, but when Wallace asked a second time, Trump responded: “Proud Boys, stand back and stand by.” He then made reference to violence on the far left. “But I’ll tell you what, somebody’s gotta do something about Antifa and the left because this is not a right wing problem, this is a left wing problem,” he said.

The reference to Proud Boys instantly stirred outrage among viewers who connected it to the Proud Boys, an organization described by the Southern Poverty Law Center as a violent white nationalist organization associated with an ideology that falls under general hate. There was also anger directed to Wallace for failing to challenge Trump on the remark.

Comedian Andy Richter said it sounded “like the words of a commander to his troops.”

Showrunner David Simon noted it as a low point for the occupant of the nation’s highest office.

Actor-comedian Billy Eichner slammed Trump for being what he termed “a vile, racist b—-.”

Actor Meredith Salenger expressed her dismay.

Actors Kerry Washington and Sophia Bush urged debate viewers to channel their anger into turning out on Election Day, Nov. 3.

Trump’s comment was among the low points of a debate marked by testy exchanges, crosstalk, personal insults and a general lack of civility during the 90-minute exchange. Biden at one point told Trump to “shut up” after repeated interruptions. Trump took aim at Biden’s son, Hunter Biden, repeatedly stating accusations that the former Vice President’s son enriched himself through corrupt means in Russia and the Ukraine while his father was in the Obama administration.