LA PAZ, Bolivia (AP) — President Evo Morales came out ahead in the first round of Bolivia’s presidential election, but he appears to have failed to get enough votes to avoid the first runoff in his nearly 14 years in power.

The preliminary results released late Sunday dealt a harsh blow to South America’s longest serving leader in what has become the tightest political race of his life. But Morales, who is seeking a fourth term, still declared victory and told supporters at the presidential palace that “the people again imposed their will.”

The Andean country’s top electoral authority said that with 83% of the vote counted from Sunday’s election, Morales was in first with 45.3%, followed by former President Carlos Mesa with 38.2% for second place in the field of nine candidates.

A special electoral mission from the Organization of American States said it was closely monitoring the election and requested information from the Supreme Electoral Tribunal after the transmission of preliminary results was halted.

If the results hold, Morales and Mesa will face off in a December ballot in which Morales could be vulnerable to a united opposition.

“We’re in a runoff,” Mesa told supporters shortly after the first results were announced. He said his coalition had scored “an unquestionable triumph,” and called on others parties to join him for a “definitive triumph” in the second round.

Morales, 59, a native Aymara from Bolivia’s highlands, came to prominence leading social protests and rose to power as the country’ first indigenous president in 2006. Since then, he coasted to two re-election victories and presided over more than a decade of business-boosting economic growth in South America’s poorest country. Following a boom in commodities prices, Morales paved roads, sent Bolivia’s first satellite to space and curbed inflation. Stadiums, markets, schools, state enterprises and even a village bear his name.

Mesa is a 66-year-old historian who as vice president rose to Bolivia’s top office when his predecessor resigned the presidency in 2003 amid widespread protests. Mesa then stepped aside himself in 2005 amid renewed demonstrations led by Morales, who was then leader of the coca growers union.