Security forces in Kananga clashed with militia fighters seeking to avenge the death of their leader who was killed in August by the military, officials and media reports say.
The fighters attacked the city's airport on Friday, killing an airline worker, witnesses said.
DR Congo has suffered from years of unrest and political instability.
Protests against President Joseph Kabila in the capital Kinshasa earlier this week left at least 50 people dead, the UN said.
Reports said fighters loyal to late tribal chief Kamwina Nsapu first entered Kananga on Thursday morning.
Broadcaster Radio Okapi said the militia clashed with security forces and were eventually beaten back.
They returned on Friday and attacked the airport.
"There was heavy fighting with small arms and heavy weapons," said witness Killy Ilunga, who saw the body of a dead flight attendant.
"They burst into the hall of the airport. One of them beat her with a club."
Another witness reported seeing the bodies of several militia fighters at the airport.
The number of deaths has not been confirmed but reports put the toll at between 10 and 13.
Government spokesman Lambert Mende said the situation was under control.
"The airport has been under the control of our forces since this afternoon," he said. "We don't have a death toll at the moment. But yes, there were deaths."
Two days of violence in a city in central Democratic Republic of Congo have left at least 10 people dead.