Leftist protesters trying to force out the Oaxaca state governor set fire to another building Sunday after a night of burning vehicles and government offices in running street battles with police that injured at least 43 people.
The violence broke out late Saturday after masked youths broke away from a protest march by about 4,000 people and began attacking police and buildings in this picturesque state capital.
Mexican youths hurled rocks, fireworks and gasoline bombs in a failed attempt to encircle federal police holding the main square, which security forces took back in late October after protesters had held it for months demanding the resignation of Gov. Ulises Ruiz.
Police drove off the attackers with tear gas and jets of water from tanker trucks, then advanced in massed ranks to drive protesters from a camp at a smaller plaza two blocks away.
But bands of young people rampaged through downtown, pushing shopping carts loaded with rocks and gasoline bombs.
Court offices in one of Oaxaca's imposing colonial buildings were gutted by flames, and the gangs burned 20 private vehicles and attacked three hotels, throwing firebombs at one and smashing windows at the others.
Fires also damaged four buildings that house government offices, one university building and the state hotel association.
The federal police said 152 people had been arrested and four officers injured. A spokesman for the anti-Ruiz movement said some protesters suffered serious injuries.
Firefighters had quelled the blazes by early Sunday, but protesters later set fire to a tax office.