NEW : Four police officers are hurt , one is arrested . December : Two officers are arrested . Police angry over a decision to stop flying the American flag year - round . Police say 66 officers injured , 100 arrests made since December .
NEW : Four police officers are hurt , one is hospitalized . NEW : Two people are arrested . Protesters angry over a decision to stop flying the Union flag year-round . Police say 66 officers injured , 100 arrests made since December .