A dissident faction of Mexico's teachers' union is under fire for publicly humiliating teachers and administrators who defied its strike.

Several school workers were seized in the southern town of Comitan on Tuesday. They were marched barefoot through town with signs hanging around their necks saying they were "traitors to the country."

The hair was forcibly cut off several of them as a crowd watched.

The victims had been carrying lists of teachers who had attended classes so they would not be fired for absenteeism under reforms the radical faction opposes.

Education Secretary Aurelio Nuno says he'll work with prosecutors to punish those responsible.

The leader of the faction appeared to defend the shaming on Tuesday, but as criticism mounted on Wednesday, he blamed it on government-planted infiltrators.