Florentino Lopex Martinez, a protester, said: "This is a policy of oppression, the most fascist type of oppression in the whole of Oaxaca’s history. The methods of repression have worsened considerably."
In 2006, protesting teachers had siezed the main plaza demanding better working conditions.
They complained that Ortiz was corrupt and came to office through a stolen election.
The protest developed into a broad demonstration against social and economic conditions in the poor Mexican state.
State and federal police violently cracked down on the protest leaving at least 27 people dead.
Witnesses claim gunmen supporting the governor fired into a crowd. There have been no convictions for the killings as yet.
His opponents say Ortiz uses violence to suppress his political opponents.
Amnesty International has said that his administration has been behind the murders of dozens of opposition members.
National and international human rights organisations say most of the violence now takes place in remote villages of Oaxaca.
Talking to Al Jazeera, Ortiz said: "There is no documentation to implicate any government official. Amnesty International's report is totally partial."
Ortiz's Institutional Revolutionary Party (PRI) has ruled Oaxaca for nearly 80 consecutive years.