Hundreds of gunmen attacked official installations in Democratic Republic of Congo's southern mining hub of Lubumbashi before being repelled by soldiers, the government said on Saturday.
The attack on the capital of the central African nation's copper and cobalt-rich Katanga province began around 1 PM (14.00 GMT) and targeted a military camp and the provincial governor's office, sending the city's residents fleeing home.
"They were driven out and suffered heavy losses among their ranks ... There were several hundred of them," Information Minister Lambert Mende told Reuters.
"The shooting lasted one or two hours. We will provide a full account of events in the coming hours," he said.
Mende said Congolese authorities were still attempting to identify the gunmen after some witnesses said they appeared to belong to one of Congo's mystical Mai Mai armed militia groups.
A resident contacted by Reuters said he had seen the bodies of five attackers killed by gunshots near the governor's office.
He said the group wore traditional magical fetishes and had attempted to hoist the flag of Katanga's short-lived 1960s-era independent republic before members of the army's elite Republican Guard launched a counter-attack against them.
"They came out of nowhere," said the witness, who said he had seen around 300 gunmen. "Then they just vanished."
Soldiers continued to occupy important locations throughout the city in the late afternoon as traffic began to circulate again.
Millions have died in the vast former Belgian colony's long-simmering armed conflicts, but - with fighting concentrated in the country's eastern borderlands - the mining areas around Lubumbashi have remained relatively calm.
Katanga now hosts many international mining companies, including Freeport McMoRan and commodities trader Glencore, and exports around half a million tonnes of copper each year.
Unidentified gunmen attacked Lubumbashi's airport last August - the second attack on the facility in two years - killing at least one soldier as government forces repelled the offensive after several hours of fighting.