Bolivia's electoral authority announced Monday night that President Evo Morales was close to avoiding a runoff in his re-election bid, touching off protests by the leader's opponents already upset by a sudden halt in the release of the vote count.
A crowd burned the offices of the electoral body in the southern city of Sucre, and groups of Morales' supporters and opponents clashed in a number of places.
The president's opponents suggested that officials were trying to help Morales avoid a runoff fight in which he could lose to a unified opposition, while an observer mission from the Organization of American States expressed concerns about the development.
A US State Department accused Bolivian authorities of trying to subvert the vote.
Morales topped the eight other candidates in Sunday's presidential election, but the last released results before Monday night showed him falling a few points short of the percentage needed to avoid the first runoff in his nearly 14 years in power.
Still, he claimed an outright victory late Sunday, saying the uncounted votes would be enough to give him a fourth term.
He told supporters at the presidential palace that "the people again imposed their will."
Mesa, who had warned earlier that there could be "manipulation of the vote to impede a second round" of voting, called on citizens and civic groups "to conduct a battle in defence of the vote."
The OAS observer mission issued a statement calling on electoral officials "to firmly defend the will of the Bolivian citizenry."
Michael G Kozak, acting assistant secretary at the US State Department's Bureau of Western Hemisphere Affairs, said on Twitter that "the US rejects the Electoral Tribunal's attempts to subvert Bolivia's democracy by delaying the vote count."
The interior minister, Carlos Romero, accused the opposition of trying to create trouble, warning that "they have to take care of the violence they're generating."
"International support would be weak, as there is little appetite in the region to contest Morales' legitimacy."
Disclaimer: No Business Standard Journalist was involved in creation of this content