Bolivia braced for a general strike on Tuesday hours after violence broke out in several cities when the main opposition candidate rejected presidential election results that seemed set to hand a controversial victory to long-time incumbent Evo Morales.
Opposition supporters reacted with fury, torching electoral offices in the southwestern cities of Sucre and Potosi, while rival supporters clashed in the capital La Paz.
Incidents were reported in cities across the South American country.
Carlos Mesa, who came a close second to Morales in Sunday's polls -- forcing a run-off, according to preliminary results -- denounced revised results released by election authorities as a "fraud."
The United States' top diplomat for Latin America said the Electoral Tribunal was attempting "to subvert Bolivia's democracy by delaying the vote count and taking actions that undermine the credibility of Bolivia's elections."
"It is extremely important that calm is maintained and any form of violence is avoided in this delicate situation."