CARACAS, Venezuela — Hugo Chavez sought to cement his power and end presidential term limits in a vote Sunday that the government and opposition said was too close to call.

“The result of the referendum is close,” Vice President Jorge Rodriguez said from Chavez’s campaign headquarters. “We will respect the result, whatever it is – even it’s by one single vote.”

He said some polling stations remained open late and the electoral council was still awaiting results from 20 percent of them.

“We’ll honor the referee’s decision, and we call on the other side to do the same,” Rodriguez said.

Opposition leader Julio Borges also said the results were very close, likening the vote to a photo finish.

Caravans of Chavez’s supporters took to the streets honking horns and blaring celebratory music as they anticipated victory after most polls closed. Opposition leaders did not concede and called for their supporters to closely monitor the ballot count.

Chavez’s opponents fear a win by the president could mean a plunge toward dictatorship by the leader bent on turning this major U.S. oil provider into a socialist state. Supporters have faith that Chavez would use the reforms to deepen grass-roots democracy and more equitably spread the wealth.

An emboldened opposition and violent clashes in recent weeks prompted fears of bitter conflict if either side disputed the results, which pollsters had predicted to be close.

Two pro-Chavez officials told The Associated Press their exit polls show a victory for the reforms, but an opposition campaign official said its poll shows Chavez headed for defeat. All spoke on condition of anonymity because of election rules barring the early release of results.

Associated Press writers Frank Bajak, Edison Lopez, Fabiola Sanchez, Jorge Rueda, Christopher Toothaker and Sandra Sierra contributed to this report