LA PAZ, Bolivia (AP) — Police in Bolivia have fired tear gas and rubber bullets at protesters marching toward the presidential palace as tensions over a disputed election escalated.

Masked demonstrators set fire to barricades and threw tear gas back at police lines during the clashes in La Paz before dawn Friday.

The protesters oppose Bolivian President Evo Morales, who was declared the winner of the Oct. 20 presidential vote. The opposition alleges the outcome was rigged to give Morales enough of a majority to avoid a runoff election; the president denies any irregularities.

Two people were fatally shot at around midnight Wednesday during clashes between supporters and opponents of Morales in Santa Cruz province, an opposition stronghold.