Members of a prominent white nationalist group have pledged to provide some unsolicited protection to supporters of Donald Trump at next month’s Republican National Convention in Cleveland, Ohio.

Traditionalist Worker Party spokesman Matt Parrott told McClatchy on Monday that about 30 members of his group, which held a rally at the California state capitol over the weekend where at least five people were stabbed, will head to the convention to “make sure that the Donald Trump supporters are defended from the leftist thugs.”

That was the thinking behind Sunday’s rally in Sacramento, which was organized along with the Golden State Skinheads: to publicize what they see as acts of aggression against Trump supporters. The rally dissolved into chaos, with anti-fascist and anarchist protesters physically clashing with the approximately 30 skinheads who showed up at the event. At least 10 people were injured.

No one has yet been arrested for the brawl, but police told the Sacramento Bee that there were injuries on both sides.

The altercation heightened concern about the potential for violence at the July convention, where other groups including Bikers for Trump, Truckers for Trump and the Cleveland Tea Party have promised to hold pro-Trump events. Thousands of opponents of the divisive GOP nominee will also converge on Cleveland.

City officials claim that they’ve thoroughly prepared a plan for the convention. This security preparation so far has involved ordering Cuyahoga County to clear the dockets for arrests made during the event, reserving 200 beds for arrestees, and ordering new gear including 100 body cameras and 2,000 riot control suits.

Parrott told McClatchy that the heavy police presence would prevent any large-scale acts of violence, although “there might be a couple of isolated skirmishes.”

Still, the brawls that have broken out at dozens of Trump campaign events are already casting a shadow over the upcoming convention. Matthew Heimbach, head of the Traditionalist Worker Party, was one of several white Trump supporters who forcibly ejected a black protester from a Louisville, Kentucky rally in March.

The Southern Poverty Law Center, which tracks hate groups, has described Heimbach as “the face of a new generation of white nationalists.”