The women, said to be Hutu, were reportedly dragged off from a minibus, before they were lynched and their bodies set on fire by a crowd on Wednesday.
Dozens have died in tit-for-tat killings by ethnic militia this year.
Ethnic rivalries, invasions by Rwanda and Uganda and competition for land and minerals among eastern Congo’s dozens of rebel groups have stoked conflict over the last two decades.
“I condemn the death of these two women,” said Mayor Sikuli Uvasaka Makala.
“I insist: stop carrying out popular justice. Do you want to put the Nande community at risk?”