Sacramento Fire Department spokesman Chris Harvey said two of the injured got critical stab wounds.
The injured - nine men and one woman - were between 19 and 58, the fire department said in a tweet, and all had multiple stab and laceration wounds. Harvey said one of the injured refused to go to the hospital.
The Traditionalist Worker Party, or TWP, whose leader describes it as a "white nationalist" group, were permitted to hold a rally at noon near the state Capitol, said Officer George Granada, California Highway Patrol public information officer with the Capitol Protection Division. Another group showed up "to stop them from carrying on their permit," he said.
"They (counter-protesters) showed up ahead of time in a large group, probably 300 or more," Granada said. "They were positioned around the Capitol to stop them (TWP demonstrators) from carrying on their permit," he added.
According to Granada, around 11:45 a.m. PT, TWP members and supporters came out to a location south of the Capitol building. He did not specify the number of TWP members, but said they were clearly outnumbered.
"At that point the word spread pretty quick and a mob ran in that direction and they clashed immediately with each other," he said.
Sacramento Police Department Officer Matt McPhail said the stab wounds of the victims required critical medical care, said. It is learned that no one sustained life-threatening.
Yvette Felarca, who said she was a member of the group By Any Means Necessary, said that she decided to come out to let people know that racist and anti-immigrant viewpoints would not be tolerated.