Two officers were in a vehicle that was fired on in the Orangi Town neighborhood late in the day, Dawn News reported. No suspects had been identified, police said.
Another police officer shot earlier in the day in a separate incident, died in a hospital, police said.
Other victims included two madrassa students. After they were killed, protesters blocked roads and set tires on fire in the Nipa Chowrangi district.
Two brothers were also killed in another attack.
A juice shop was attacked, killing the owner and two customers, police said. Four others were injured.
Store owners in the area around the juice shop were told to close up by midnight.
Three other people were killed in two shooting incidents.