Four Tanzanian police officers have been detained after two people were killed during a protest over alleged witchcraft killings.
A regional commander told the BBC that police had opened fire in the south-eastern town of Songea to stop an angry crowd from smashing public property.
The protesters said not enough had been done to find those behind the recent killing of six women.
Police deny the murders were done to obtain body parts for witchcraft use.
In recent years, there have been a spate of killings of people with albinism in Tanzania.
Their body parts are prized in parts of Africa, with witch-doctors claiming they have special powers to bring success in business and love.
The women killed in the Songea area were not believed to be albinos.
Ruvuma regional police commander Michael Kamhanda told the BBC that police officers "were forced to use live bullets" after they "had exhausted all means to disperse rowdy crowds".
Thousands of people took to the streets of Songea on Wednesday - after four women were killed and their bodies allegedly mutilated last week.
They attacked the police station and several government offices - and were heading towards a presidential residence when officers opened fire, Mr Kamhanda said.
Two other people were killed during a stampede, the AFP news agency reports.
A total of six women have been killed in the area since November - but Ruvuma police say there is no evidence, despite a widespread belief among local residents, that the killers cut off parts of the bodies for use in witchcraft.