A demonstrator at a St. Louis rally for GOP front runner Donald Trump had his face bloodied and was taken to an ambulance by police officers, according to video posted online and the New York Daily News.

The African-American man is a locally-known activist named Anthony Cage. He became a local activist against police violence and racism after the killing of unarmed black teen, Michael Brown, in 2014, by Ferguson police officer Darren Wilson.

Cage can be seen with his hands bound by plastic ties, being taken to an ambulance by St. Louis police officers. According to reporter Junius Randolph, Cage was not under arrest and was released after his wounds were treated.

Two men, one bloody, were just arrested at the Trump rally in St. Louis. pic.twitter.com/1r5njyvPDk

— Junius Randolph (@JuniusRandolph) March 11, 2016

@JuniusRandolph correction. This guy was not technically arrested. Police let him go after his wounds were treated. pic.twitter.com/63eQ6J2nEX

— Junius Randolph (@JuniusRandolph) March 11, 2016

According to the Daily News, Cage was using a bullhorn outside the Friday morning rally to denounce Trump as a racist. As he is walking with the police officers, he says something about being attacked.

A bloodied man dragged from Trump rally. pic.twitter.com/eyQxFL8Uht

— Trymaine Lee (@trymainelee) March 11, 2016

The incident occurred at a racially-charged event that had thousands of Trump supporters lined up to hear the former reality television star-turned politician speak.

Tensions were high and Trump supporters were caught on video screaming profanities and hateful rhetoric at protesters. Cage can be seen on a megaphone and getting jostled into a crowd during a confrontation between Trump supporters and demonstrators, but it’s unclear how he ends up getting hurt.

St. Louis Trump rally. pic.twitter.com/qimlRPLOz8

— Junius Randolph (@JuniusRandolph) March 11, 2016

Cops are coming in pic.twitter.com/MpKL5LdwoP

— Junius Randolph (@JuniusRandolph) March 11, 2016

Inside the rally, Trump was interrupted frequently by demonstrators, when he yelled to “get them out.” He commented that it was a shame protesters had to be treated “gently” by the police.

At one point he said protesters think “there are no consequences to protesting any more. Our country has to toughen up folks.”

Trump informs crowd he is currently fantasizing about doing something to protesters, but “won’t say what’s on my mind.” Crowd goes wild. — Angelo Carusone (@GoAngelo) March 11, 2016

Several incidents of violence revolving around the Trump campaign are currently being investigated by the authorities, including a supporter assaulting a black protester in North Carolina and a conservative reporter accusing his campaign manager of roughing her up.