CLEVELAND, United States (AFP) — Scuffles broke out between opposing protesters in Cleveland on the second day of the Republican National Convention.

A planned demonstration against police shootings of African-Americans devolved into mayhem, with punches thrown and shouting matches.  

Approximately 100 police officers separated the duelling groups and maintained a strict cordon, quickly defusing tensions between rival protesters — who also numbered around 100.  

There were no immediate arrests, according to Cleveland Police Chief Calvin Williams, who was at the scene.    

With calm restored, some of the protesters marched through one of downtown’s busy thoroughfares, with police and media in tow.  

They carried a large banner with faces of African-Americans under the title “Stop Murder by Police.”  

“Look at these faces, all of them people whose lives were stolen by law enforcement,” said one protester over a loudspeaker.  

Joining the march midway was actor William Baldwin, who said fully supported the work of police, but also shared the mounting concerns about fatal shootings of black Americans.  

“The vast majority of the cops are good and are well trained,” Baldwin told AFP during the march, “But I think police practices and procedures have to change. Have to. It doesn’t work.”

As the protest was getting under way, witnesses said Alex Jones — a controversial radio show host who espouses various conspiracy theories — challenged the assembled crowd. A few protesters began shouting “Nazi scum” and at least one of them attacked Jones.  

The ensuing scuffle happened in front of Chief Williams, and police immediately moved in to separate the two sides.   

Another group of counter-protesters, with signs including one that said “Every Real Muslim is a Jihadist,” needled the crowd.  

They were met with a chorus of boos, and comments such as “You’re miserable.”  

Other protesters were yelling: “Indict! Convict! Send the killer cops to jail! The whole damn system is guilty as hell!”

The refrain has been a common one in various protests since Sunday.  

News media swarmed the scene — on alert for trouble between rival protesters since the opening of the party convention, which Tuesday saw Donald Trump officially nominated as the Republican candidate for president.    

Officials have set up tight security zones and remain on heightened alert as groups with various messages plan protests.