The fire at the electoral building broke out at about 2 a.m. local time, after a wave of violence in the capital, Kinshasa.

A thick, black cloud of smoke still hung above the city on Thursday morning.

President Joseph Kabila's chief advisor Barnabe Kikaya bin Karubi said some 7,000 voting machines had been destroyed. He blamed unidentified "criminals" for the blaze, 10 days ahead of a long-awaited presidential election.

Kikaya said police who were guarding the warehouse had been arrested, although he made no further comment on what or who had caused the fire.

The number of destroyed machines represents some 70 percent of those that were due to have been used in the capital. Kikaya said machines would be recalled from other parts of the country for use in the capital, which is home to 15 percent of the nation's population.

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According to the country's Independent National Electoral Commission, materials for 19 of the 24 polling stations for Kinshasa had been destroyed.

"We're still working and evaluating everything. So far, we have no reason to assume that the fire will stop the election process," head of the commission, Corneille Nangaa, told DW. "It will obviously have an influence, but the process will not be interrupted."

On Wednesday, clashes had erupted in Kalemie, a town on Lake Tanganyika, as opposition candidate Martin Fayulu was there to campaign.

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Incumbent President Joseph Kabila, who has been in power since the assassination of his father in 2001, has been due to step down because of constitutional term limits. However, the vote — slated for December 23— has already been delayed by two years because of what authorities termed "logistical challenges."

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rc/sms (Reuters, AP, AFP)