Zambian troops entered a slum in Lusaka to restore order after residents rioted over a curfew and ban on street vending imposed to control a cholera outbreak, state radio said.
The riots in the densely populated Kanyama township were sparked after police sealed off a market where trading had been banned, when the curfew was declared.
Cholera killed more than 60 people in the Zambian capital since it broke out there in October.
Street vending and public gatherings were banned across Lusaka to prevent the spread of the disease, but residents of Kanyama, where around 370,000 people live, have been defying the order at night.
The army was deployed after locals destroyed property and looted shops, the Zambia National Broadcasting Corporation said.
Reuters could not immediately confirm that troops entered Kanyama, but Local Government and Housing Minister Vincent Mwale said police were sent there to stop rioting.
Peter Zulu, a local resident, said rioters blocked Los Angeles Road, a major thoroughfare, and police had fired teargas to disperse them.
Main opposition leader Hakainde Hichilema called for calm in Kanyama, a stronghold of his United Party for National Development.