International monitors expressed concern over Bolivia’s presidential elections on Tuesday after an official quick count showed President Evo Morales near a first-round victory despite a more formal tally suggesting he was heading for a risky runoff.

The European Union and Organisation of American States (OAS) expressed alarm after Mr Morales suddenly shot upward in the quick count on Monday following a day-long pause in results.

The last numbers released before Monday night had shown Mr Morales topping the eight other candidates, but also falling several percentage points short of the percentage needed to avoid the first runoff in his nearly 14 years in power.

Yet the president claimed an outright victory late Sunday, telling supporters the votes still to be counted — largely from rural areas where he is most popular — would be enough to give him an outright victory.

On Monday, the electoral tribunal suddenly released an updated figure, with 95% of votes counted, showing Morales just 0.7 percentage points short of the 10-percentage point advantage needed to avoid a runoff.

Bolivia Elections
Bolivia’s President Evo Morales speaks during a meeting with Organisation of American States delegates in La Paz on Tuesday (Juan Karita/AP)

But a more formal official count running simultaneously, if more slowly, showed a closer race: With just under 96% of polling places counted in that process as of late Tuesday, Morales led by 8.45 percentage points.

The EU said in a statement: “The unexpected interruption of the electronic vote counting after the first round of the general elections in Bolivia has sparked serious concerns that need to be fully and swiftly addressed.”

The OAS observer mission issued a statement calling on electoral officials “to firmly defend the will of the Bolivian citizenry”.

Mr Morales’ opponents burned election offices and ballots in several cities and called for a strike on Wednesday, accusing the leftist leader of trying to avoid a December runoff in which he would confront a united opposition.

Rioting was reported in several of Bolivia’s nine regions. In the capital La Paz, police used tear gas trying to quell fighting between supporters of Mr Morales and his chief rival candidate, former president Carlos Mesa, outside a vote-counting centre. Protesters threw firecrackers and stones.