Schools in conflict-ridden Oaxaca City were declared officially open Thursday after a six-month of teachers strike, but only a small percentage held classes due to ongoing teacher-parent conflicts, state officials said.

More than 1 million children had been out of the classrooms since late May when teachers went on strike across the southern Mexican state.

On Oct. 26, the educators agreed to accept pay raises and go back to work. Most schools opened soon after outside the capital, but instructors in Oaxaca City said unstable conditions there made it impossible to restart classes.

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The city continues to suffer from clashes between police and protesters who are demanding the resignation of state Gov. Ulises Ruiz.

What began as a teachers strike mushroomed in June into a wider protest movement involving various social and political groups. More than 4,000 federal police sent to the city by President Vicente Fox last month cleared the central square of protest camps but failed to quell the unrest.

Oaxaca has 13,000 public schools statewide, 2,500 of which are located in the capital of the same name. Yet only 350 city schools opened their doors to students Thursday, said state education director Abel Trejo. He did not provide the total number of students who returned to class.

Trejo cited at least two reasons for the poor attendance: There are still teachers who don't agree with the decision to end the strike, and some parents are angry with teachers and no longer want them instructing their children.

"I'm afraid that they're going to teach the children how to make gasoline bombs," said one parent, Ernestina Gomez, referring to the homemade weapons that some protesters have used during scuffles with police.

"I can't believe the teachers have the gall to return after months (away)," added parent Patricia Juarez Perez.

Ruiz, whose term ends in 2010, has refused calls to step down — some of them from within his own Institutional Revolution Party, which ruled Mexico for 71 years and often rigged elections before losing the presidency six years ago.

On Wednesday, the U.S. Embassy announced it was extending a travel warning advising U.S. citizens to avoid travel to Oaxaca and to "remain vigilant" throughout the country, citing recent bombings in Mexico City.