UPDATE 1-Bolivia debates validity of autonomy vote

(Adds reaction from OAS, U.S.)

By Pav Jordan

SANTA CRUZ, Bolivia, May 5 (Reuters) - Local authorities in Bolivia's wealthiest region claimed victory on Monday in their unprecedented weekend vote for autonomy, but the central government said abstentions made the vote invalid.

The vote in agricultural and energy producing Santa Cruz was a repudiation of the leftist reform agenda of President Evo Morales, the first indigenous president in Bolivia, South America's poorest country.

"A complete success for democracy," said the Santa Cruz electoral court, which said that with more than a third of votes counted, 84 percent voted for autonomy, and 16 percent against. At least 18 people were injured and one man died during clashes between pro-autonomy and government backers during the voting.

The electoral court and the central government agreed that some 36 to 40 percent of eligible voters boycotted polls, and the central government said that was high enough abstention to make the vote invalid.

"What is notable here is the phenomenal level of abstention," said Juan Ramon Quintana, Morales' cabinet chief. "This vote was illegal. Shouldn't we note how many people abstained here?"

The vote theoretically would allow Santa Cruz to elect its own leaders and create its own tax and justice system and also to control its own natural resources, including about 10 percent of Bolivia's oil and natural gas reserves.

"Things are going to change because we are going to be able to manage our own resources and elect our own governors," said Jose Castro, 50, a chauffeur.