LUBUMBASHI - Gunmen yesterday attacked vehicles carrying ballot papers to a polling station in the Democratic Republic of Congo's city of Lubumbashi.

Police said the attackers swooped on a convoy of eight jeeps at around 3am and fled when police escorting the vehicles opened fire, wounding some of the assailants.

Two jeeps carrying nearly 1000 ballot papers were burned in the attack. Later, residents of the area showed journalists presidential ballots that they said had already been marked when they found them.

Meanwhile, gunfire shots were heard in the city around midday, causing panic in Njanja district, with people running for cover. It was not immediately clear where the shots were coming from or why.

The shooting continued, though with less frequency. An ex-member of a Katanga separatist group fighting for the province's independence said the group had carried out the ambush on the election convoy.

"We want a self-determination referendum, and not this vote that doesn't have anything to do with us in Katanga," the self-described Lieutenant Chana Kazi said by phone from South Africa.

He also claimed a Sunday attack by gunmen who raided a military camp and arms depot in the city, killing one person and fleeing after exchanging gunfire with soldiers.

Lubumbashi, the restive capital of the mining province of Katanga, had been a flashpoint of political violence in the run-up to yesterday's elections. Earlier this month, two days of street fights between opposition and government supporters shut down parts of the city. Banks and other businesses closed amid unrest in which shop windows were shattered and pedestrians mugged.

On Sunday, gunmen attacked a military camp and arms depot in the city, killing one person and fleeing after exchanging gunfire withsoldiers.

Provincial authorities said they had arrested three of the attackers, suspected of being separatist militants fighting for the province's independence.