Protesters set fire to another building in the colonial city of Oaxaca on Sunday after torching government offices and vehicles and damaging hotels during demonstrations that left at least 43 injured and 152 arrested.
On Saturday, leftist protesters demanding the resignation of the Oaxaca state governor hurled rocks, powerful fireworks and gasoline bombs at federal police, in a bid to encircle the officers in the picturesque, arch-ringed main square of the city.
Police used tear gas and water jets from tanker trucks to force back the protesters and retake another, smaller square nearby where the demonstrators had regrouped after police re-entered the city in late October, ending a five-month takeover.
On Sunday, the federal police who have largely remained in the main square and a few positions around the city announced they would actively patrol the city in search of those who committed "direct attacks on federal police."
In a press statement, the police said four of their officers and several bystanders were injured in the confrontation and accused outside activists of participating in the unrest.
During the clash, bands of masked youths broke off from a march of about 4,000 people earlier Saturday and pushed shopping carts filled with rocks and gasoline bombs through the streets in a running battle with police.
By early Sunday firefighters had controlled the blazes, but the flames had already gutted court offices housed in one of Oaxaca's imposing colonial edifices. Later Sunday, protesters also torched a tax office.
In one of his first public appearances downtown in his own state capital since protesters forced officials out in May, Gov. Ulises Ruiz vowed to punish those responsible and remove the barricades protesters still man in some sections of the city.
"All the weight of the law will be applied to those who have committed these acts of vandalism," Ruiz told reporters.
Federal police said 152 people were arrested. Ruiz put the number at 160 and state prosecutors said that at least 43 people were injured; it was unclear whether that figure included ten police officers and three journalists who suffered minor injuries in the confrontations.
Prosecutors said there were no reports of any deaths; many of the injuries appeared minor, involving tear gas inhalation or blows from rocks and cudgels.
Downtown residents watched in horror as buildings went up in flames and the streets filled with a choking mixture of tear gas and smoke.
Oaxaca resident Josefina Quiros said protesters loosely organized under the leftist People's Assembly of Oaxaca were spreading fear.
"We are terrified of the APPO people," said Josefina Quiros, referring to the assembly by its Spanish initials.
The protesters are demanding the resignation of Ruiz, accusing him of brutality, corruption and electoral fraud.
Demonstrators attacked three hotels, hurling gasoline bombs at one and smashing windows at two others. Some protesters also looted several business in the downtown area.
The fires damaged four buildings housing government offices, one university building and the offices of the state hotel association, which had already seen business from tourism the city's main source of outside income reduced to a trickle by the six-month-old protest movement.
In late October, the federal police retook control of the city's picturesque main square from protesters stationed there since May, but their control over the rest of the city has been tenuous since then.
On Saturday, police advanced in formation from the main square to oust demonstrators from the protest camp they had set up in another square, the Santo Domingo plaza, two blocks away.
Marcelino Coache, a spokesman for the leftist People's Assembly of Oaxaca, said some protesters suffered serious injuries; some of the demonstrators appeared to have retreated to the campus of a local university, where academic-freedom laws prevent police from entering.
Gov. Ruiz earlier blamed the disturbances on radical groups from Mexico City.
"These are the death throes of a movement that has already disintegrated," Ruiz told a news conference Saturday.
The conflict began months ago as a teachers' strike, but quickly mushroomed into a broad protest against social and economic injustices in the poor state; protesters seized and paralyzed much of the city between May and October.
A majority of the teachers have since returned to work and did not participate in Saturday's demonstration.
Nine people have been killed in the clashes, including freelance video journalist Bradley Roland Will, 36, of New York, who was filming a group of leftist protesters that clashed with a group of armed men. Both sides fired, and it is not clear who shot first.
Several governments, including the United States, have warned tourists to stay away from Oaxaca city, formerly popular with tourists for its nearby ruins, cuisine, colonial architecture and handicrafts.