A huge cloud of black smoke and large flames could be seen in aerial images of the Superior Court of Electoral Justice (TSJE) in the capital of Asuncion, which houses material and machines that will be used in the elections and where hundreds of officials work.

"We have suffered serious damage ... they are fighting to try to prevent (the fire) from spreading to other rooms," Asuncion's electoral Justice Jorge Bogarin told a local radio station, adding there were no immediate reports of any deaths.

Bogarin said the cause of fire could not be confirmed yet, but that the incident could "eventually alter the schedule that was already drawn up" for coming elections.

He also said that a committee would be created to investigate the fire's origin and find ways to ensure the elections are held.

Primaries for presidential candidates are currently scheduled for Dec. 18 and general elections for president, vice president, governors and congressmen are scheduled for April 30 of next year.

TSJE President Jaime Bestard said in a news conference that the fire may have damaged some 8,500 voting machines and that he would look into holding December's primaries in two different stages.

Opposition figures immediately questioned the idea.

"Breaking the elections up is a plan to carry out fraud," said Efrain Alegre, president of the opposition Liberal Party.

"The law establishes that the primaries are held at the same time as a way to prevent voters from fraudulently voting in two primaries," Alegre said.