The clash occurred during a march by The Proud Boys along Water Street in the city, where they were met by counter-protesters, FOX 17 of Western Michigan reported.
A local pastor had urged participants to refrain from violence, MLive.com reported.
“Let’s work together to remain peaceful and manifest positive energy with each other, to take care of each other, to take care of our own selves and our own safety, and to defend one another,” the Rev. Nathan Dannison told the crowd, the news outlet reported.
The confrontation began with members of both groups shouting at one another, then continued with punches thrown and protest signs being used as weapons, the station reported.
Samuel Robinson, a journalist for the Kalamazoo Gazette, was among those detained, MLive.com reported, though the reason was not clear.
At least one man was seen with blood streaming down his face, according to FOX 17.
“We’re both covered in pepper spray, we both watched people get hit in the face,” Noelle Massey, a Kalamazoo resident who was among the counter-protesters, told the station.
“I don’t want racists having the freedom to march down our streets without repercussions,” said Darrick Hubbard, another counter-protester from Kalamazoo.
Critics have accused The Proud Boys of being anti-Muslim, anti-Semitic and anti-women, according to reports.
Police said “several” people were arrested for unspecified offenses.
The trouble ended about a half-hour after it began, reports said.