An anti-riot police vehicle fires water canon during a protest against an autonomy referendum in El Alto on the outskirst in La Paz May 4, 2008. Bolivia's richest region of Santa Cruz went ahead with a vote on greater autonomy from the central government on Sunday in a referendum that President Evo Morales declared illegal, but still poses the biggest challenge yet for his government. REUTERS/Gaston Brito(BOLIVIA)
REUTERS/GASTON BRITO