Tensions grew in this besieged Mexican city Friday with police saying three officers were beaten by protesters a day after a teacher was hacked to death.
The violence raised fears the four-month-old standoff between protesters and Oaxaca state government could lead to a wider confrontation.
Thousands of state police have gathered outside the city in recent days, and helicopters and military planes have flown over the demonstrators.
About 2,000 leftists, labor activists and Indian groups have occupied the center of this historic city since May. They are demanding the resignation of Oaxaca Gov. Ulises Ruiz, whom they accuse of rigging the 2004 election.
The standoff began when teachers went on strike for higher wages, but it quickly mushroomed into a broad-based movement. Ruiz and local business groups have asked the army to intervene to end the standoff.
About 60 protest sympathizers seized the three policemen in Zaachila, a village six miles outside Oaxaca city, state police said Friday. They said the officers were kicked and beaten for about two hours before being released.
On Thursday, a teacher belonging to a group opposed to the strike was killed by two assailants who stabbed him in the neck with an ice pick, said Oaxaca state police official Victor Alonso Altamirano. Protesters deny they were involved.
Clashes involving protesters, police and armed gangs have left two people dead, and both the U.S. and British embassies in Mexico have issued advisories warning their citizens about going to Oaxaca.
The unrest has scared most tourists away from the city, which is normally popular for its colonial architecture and ancient pyramids. Business leaders put losses at more than $300 million.