Good rundown in Afghanistanica and Asia Times. Uzbeks, led by Dostum, are basically protesting the policies of a a northern Pashtun warlord appointed by Hamid Karzai to run Jowzjan province, which is predominantly Uzbek. The deaths look to have occurred during attempted storming/protest of the governor's residence --- undoubtedly he has his own forces there (in police unis, of course) to protect him.

Note that the Iraqi tribes in Anbar (the Uzbeks are not tribal, but the center-province clash is similar) are also feuding with the Baghdad-appointed governor of Anbar.