CLEVELAND (AP): Left-leaning activist groups pushing for “economic justice” and an “America First Unity March” sponsored by Citizens for Trump will hit the streets of Cleveland.

Two groups are scheduled to hold rallies and marches Monday, the official start of the four-day Republican National Convention.

There are concerns about violent protests during the RNC between supporters and foes of presumptive Republican nominee Donald Trump.

Cleveland police reported one arrest Sunday after a man tried to grab a police officer’s gas mask.

Monday also happens to be the 50th anniversary of the beginning of Cleveland’s Hough riots. The riots that began July 18, 1966, were sparked by a confrontation between black residents and a white bar owner and led to nearly a week of looting and violence in one of the city’s east side neighborhoods.