Federal police backed by armored vehicles and water cannons tore down barricades and stormed the embattled colonial city of Oaxaca, taking control of the city center that was held by leftist protesters for five months.
A male protester was killed during a clash at a barricade. Protesters identified him as a 15-year-old killed by a bullet, while a human rights group said he died after being hit by a tear-gas canister, and that his age could not be confirmed.
Protesters broadcasting over a local radio station claimed a second body, apparently that of a protester, had been found, but gave few details. That death could not be confirmed.
On Sunday afternoon, officers entered the city from several sides, setting off fierce street battles. They marched up to a final metal barrier blocking the city center, but pulled back as protesters armed with sticks attacked them from behind, hurling burning tires. The air filled with black smoke and tear gas.
As night fell, protesters decided to abandon the center and regroup at a local university. They pledged to continue their battle to get Gov. Ulises Ruiz to resign, even as police tore down the banners and tents that had served as their headquarters for months.
"We are going to leave this area ... while we regroup," said Daniel Reyes, one of the last of the striking teachers to leave the main square. The retreat was done to "protect the safety" of protesters, he said, adding "this is not a defeat, but rather a strengthening."
Protest spokesman Roberto Garcia said 50 supporters had been arrested and police were searching houses, looking for protest leaders. Police did not immediately confirm that.
President Vicente Fox, who leaves office Dec. 1, had resisted repeated calls to send federal forces to Oaxaca until Saturday, a day after gunfire killed a U.S. activist-journalist and two residents.
The protests began in May as a teacher's strike in this colonial southern Mexican city of roughly 275,000. But the demonstrations quickly spiraled into chaos as anarchists, students and Indian groups seized the central plaza and barricaded streets throughout the city to demand the Ruiz's ouster.
Police and state forces often in plainclothes have shot at protesters, setting off clashes in which at least eight people have died.
Protesters accused Ruiz of rigging his 2004 election and using thugs to kill or crush political opponents. They say his resignation is not negotiable and they won't return home without it. The violence has driven tourists from one of Mexico's most popular destinations, forcing hotels and restaurants to close their doors, reports AP.
Once colonial and breathtaking, Oaxaca's main plaza is now covered with graffiti, having served as a home base for protesters, who first seized the area in late May.