The China Mail - Mexican police tear-gas teachers' protest 10 days before World Cup

The clash started when teachers broke through one of the metal barriers that have been set up at the entrance to the Zocalo plaza, a block from the government palace and a giant screen where fans will watch Mexico's first World Cup game on June 11.

Hundreds of riot police guarded the square behind tall temporary metal barricades.

"This event will have to be suspended," union leader Filiberto Frausto told AFP. "A cause like ours should be far above -- it's far more important than a little bit of distraction and fun."

A dissident faction of the teacher's union, or CNTE, convened the march, and has threatened to summon "millions" of teachers to the capital during the World Cup if the government doesn't fulfill their demands for salary raises and the reversal of pension laws.

One of the protesters said he was hit by an unidentified projectile, and was taken away as blood poured from a head injury.

M.Chau--ThChM