A leader of Mexico's largest leftist party led thousands of protesters in a march to the center of this historic city on Sunday, demanding the resignation of the state governor and the withdrawal of thousands of federal police.
Shouting "Freedom for political prisoners!" the demonstrators also called for the release of more than 200 people arrested in the six-month-long conflict in Oaxaca that has shattered the local economy and left at least nine dead.
Leonel Cota, president of the leftist Democratic Revolution Party or PRD, marched at the front of the demonstration alongside his party's lawmakers and Oaxacan protest leaders.
The protesters a broad front of leftists, students and Indian groups accuse Gov. Ulises Ruiz of rigging his election in 2004 and of sending armed thugs against his opponents.
They took over the center of Oaxaca for five months until thousands of federal police drove them off in clashes in October and November.
The PRD has become increasingly involved in the Oaxaca conflict after keeping its distance for months. Last week party leaders took up the cause of protest leader Flavio Sosa, who was arrested in Mexico City, calling him the first political prisoner of recently sworn-in President Felipe Calderon.
The PRD claims Calderon's victory over its candidate, Andres Manuel Lopez Obrador, in July was fraudulent and refuses to recognize him as president.
Most of the nine victims of the Oaxaca violence have been protesters who were shot by armed gangs, and activists blame local police for many of those killings.
Federal police raided the offices of the Oaxaca state police on Friday, and seized their guns to determine whether any were used in shootings of demonstrators.
The conflict has shattered the tourist industry in the city, which is famous for its colonial architecture and spicy cuisine. Although police have regained control of the city center, most foreign visitors continue to stay away.
Human rights groups have asked U.N. officials to intervene on behalf of the Oaxaca prisoners, alleging they have been tortured, sexually abused and taken to prisons thousands of miles away.
On Sunday, Ruiz announced that he had signed an agreement for more than 100 prisoners to be transferred from penitentiaries in the north of Mexico to installations close to their families in Oaxaca.
Meanwhile, about 200 demonstrators marched through Mexico City in solidarity with the Oaxaca march.