U.S. Penitentiary Atwater is on lockdown after fights erupted around 4:30 p.m. Sunday between inmates at several locations inside the prison, according to a press release.
No injuries to staff were reported.
Six inmates received puncture wounds. Of the inmates who were injured, two were treated on-site and four were taken to a local hospital for treatment. None of the injuries was life threatening, said Jesse Gonzalez, prison spokesman.
The prison is conducting an investigation. Gonzalez said homemade knives were recovered.
-- Sun-Star Staff