The protesters threw stones at police vehicles and burnt tiers near Al-Asif Square in Karachi.
The police responded by firing tear gas and baton charges to control the situation. At least seven security personnel, including three paramilitary rangers were injured during the day-long violence, police said.
Investigations Waseem Akhtar, the provincial home department advisor, said charges will be brought against the people who organised the protests and strike. He said police were dispersing a crowd when someone opened fire, killing a passer-by and wounding others.
"Police are investigating whose fire killed that man," he told reporters.
Police did not give a precise estimate of the numbers of rioters, but said the figure was in the hundreds. Karachi, a city of 15 million people, is the capital of Sindh province, where private and public vehicles are often damaged by participants in anti-government rallies.