LOS ANGELES-The Los Angeles police officers' union has filed a class-action grievance against the department for ignoring officer safety during a rally that turned violent.

The Los Angeles Police Protective League, which represents the department's 9,800 officers, says it filed the grievance Friday, alleging that superiors told officers patrolling a demonstration on Jan. 10 not to don their helmets. One officer was later hospitalized with a head injury when the rally turned violent.

Department spokesman Richard French says he has no comment on the grievance. The department has 20 days to respond. The union says it will take further legal action if it is not satisfied with the department's action.

The grievance stems from a pro-Palestinian demonstration where officers were told to keep their headgear nearby but not to wear it.