“At least four policemen were gunned down on Thursday morning raising the total death toll to 12 in past 24 hours and security concerns as paramilitary rangers were also attacked overnight. Police sources said that early on Thursday morning at least six unknown attackers riding on motorcycles surrounded a police van in buffer zone and opened fire on the patrolling van. At least two policemen were killed in the firing whereas two other were critically injured.”
Source: Gunmen kill 4 police officials: 12 dead in 24 hours in Karachi violence | GulfNews.com