(Photo: UN)

Workers in DR Congo on Friday began preparations for long-awaited elections just two days away as a pre-vote protest called by the country's opposition appeared to fail.

In Kinshasa, about 20 black cases said to contain electronic voting machines were brought in under police escort to a polling station in the district of Matonge, an AFP reporter saw.

Fears of election-day problems have soared after the electoral commission said a warehouse fire destroyed thousands of voting machines earmarked for the capital.

The commission ordered the elections, already twice delayed, to be moved from December 23 to 30 to get more time to prepare.

On Wednesday, it declared the vote would be postponed again in violence-hit parts of the country.

However, the elections will still go ahead elsewhere and the new president will be sworn in on January 18 as scheduled, the commission said, without further explanation.

The announcement prompted Lamuka, a coalition of parties supporting opposition candidate Martin Fayulu, to call for cities to be brought to a standstill on Friday.

While the call had little support across the vast country, there was violence in the eastern province of North Kivu, one of the regions where voting has been postponed.

One demonstrator was shot dead in the city of Beni and four were wounded, local sources said.

In the province's capital of Goma, youths faced off with police in the rundown district of Majengo. Police there also seized camera equipment from a Congolese journalist working for the BBC.

Around 1.25 million people in North Kivu and the southwestern territory of Yumbi are affected by the postponement, out of a national electoral roll of 40 million.

The head of the Independent National Election Commission, Corneille Nangaa, met with candidates including Fayulu on Friday and reiterated that the vote would go ahead on Sunday.

Another meeting between the candidates and observers will be held on Saturday.

- Troubled past -

The presidential election -- the Democratic Republic of Congo's first in seven years -- coincides with voting for municipal and legislative bodies.

At stake is the future of a volatile giant that has never had a peaceful transition of power in 58 years as an independent state.

It has twice been a battleground for regional wars in the past 22 years and is mired in poverty, despite mineral riches ranging from gold and uranium to copper and cobalt.

President Joseph Kabila, 47, is stepping down after nearly 18 years at the helm.

He took office in 2001 at the age of just 29, succeeding his president father, Laurent-Desire, who was assassinated by a bodyguard.

But his long tenure has been come under heavy fire from human rights watchdogs and anti-corruption monitors.

Three men are heading a field of 21 candidates in the presidential race.

They are Kabila's hand-picked successor, Emmanuel Ramazani Shadary, a hardline former interior minister; Fayulu, until recently a little-known legislator and former oil executive; and Felix Tshisekedi, head of a veteran UDPS opposition party.

But a question mark hangs over whether the vote will be credible.

The authorities have permitted some election monitors from fellow African countries but refused any financial or logistical help from the UN or western countries.

On Friday, UN Secretary-General Antonio Guterres called on all sides "to continue working together to ensure an environment free of violence so that all eligible voters can cast their ballots peacefully on election day."

- Opposition favourites? -

If the elections are "free and fair," an opposition candidate will almost certainly win, according to Jason Stearns of the Congo Research Group, based at the Center on International Cooperation at New York University.

Opinion polls indicate that Fayulu is the clear favourite, garnering around 44 percent of voting intentions, followed by 24 percent for Tshisekedi and 18 percent for Shadary, he said.

However, "the potential for violence is extremely high," Stearns warned.

Between 43 and 63 percent of respondents said they would not accept the results if Shadary is declared winner, he said.

And between 43 percent and 53 percent said they did not trust DRC's courts to settle any election dispute fairly.

The figure of Shadary is at the centre of a diplomatic storm between the DRC and the European Union that erupted into the open on Thursday.

Foreign Minister Leonard She Okitundu gave the EU 48 hours to withdraw its representative -- retaliation for sanctions against Shadary and 13 other officials accused of cracking down on dissent.

On Friday, EU diplomatic chief Federica Mogherini said "nothing could justify this arbitrary act", adding that it was "totally counterproductive and harms the interests of the population"