Two of the injured had critical stab wounds, Sacramento Fire Department spokesman Chris Harvey said.
The 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. One of the injured refused to go to the hospital, Harvey said. It was not clear how many remained hospitalized Sunday night.
The Traditionalist Worker Party, or TWP, whose leader describes it as a "white nationalist" group, had a permit for a noon rally 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."
Around 11:45 a.m. PT, TWP members and supporters came out to a location south of the Capitol building, he said. It's unclear how many TWP members participated, but they were clearly outnumbered.