Two more people have died in street battles between protesters and Peruvian police trying to close La Parada, a sprawling market in the capital, Lima.
Saturday's violence came after two people died in clashes on Thursday. More than 70 people have been arrested.
Police are carrying out a council directive to move the market from its current site due to hygiene concerns.
But vendors do not want to move to a newly constructed market which they say is too small and its rents too high.
The existing market is known as a place to buy stolen goods and contraband, say correspondents.
The two people killed on Saturday were said to be civilians. Another 27 people were reported injured.
Lima's Mayor Susana Villaran, who wants to move the market to a modern site a short distance away, has accused stall-owners of hiring criminals to throw rocks and clubs at riot police.
Police responded by firing tear gas and pistols, as well as using batons.
"All the real merchants who don't rely on criminals have said they want to move to the new market," Mrs Villaran, who hopes to be re-elected in polls before the end of the year, told RPP radio.
"We are regaining order and security in an area that has only been one of disorder, chaos, insecurity and filth."