"Mobondo" militants attacked the village of Batshongo, in Kwango province, late on Friday, said provincial government spokesman Adelar Nkisi, referring to a militia from the Yaka community.
Two soldiers, one police officer and two civilians were killed in the attack, Nkisi stated, adding that the soldiers had been "practically chopped to pieces".
But later on Saturday, the spokesman said the death toll had risen to 11 people.
Clashes had occurred on in Batshongo on Friday night and continued the following day in Mongata, a village about 8 kilometres (5 miles) further west, in the capital province of Kinshasa.
Nkisi added that Kwango's government had set a curfew from 8 p.m. until the early hours Sunday morning to the respond to the emergency.
Neither a police nor an army spokesperson could be reached for comment.
Symphorien Kwengo, a Kwango civil society leader, gave a much higher death toll. He said that eight people had been killed in Batshongo and 11 in Mongata.
Conflict in western regions of DRC first erupted last year, in the Kwamouth territory of Mai-Ndombe province, in a dispute over customary tithes between the Teke and Yaka communities.
The Teke consider themselves indigenous to the region, as opposed to the Yaka and other communities whom they see as newer arrivals.
Tensions over a hike in a customary tax paid to Teke chiefs – paid by all communities, including Teke farmers – appeared to have boiled over in June 2022, according to Human Rights Watch (HRW).
At least 300 people have been killed since then in Mai-Ndombe, HRW said in a report in March.
But the attacks in the rural province are difficult to verify, and some observers argue that the number of people killed is likely much higher.
The fighting has since spilled over into the neighbouring province of Kwango as well as the capital province of Kinshasa.
On Thursday, a soldier and four militants were killed in an alleged Mobondo attack in the village of Nguma in Kinshasa province, just 75 kilometres (45 miles) from city centre of the sprawling capital.
The festering conflict in western DRC has been largely overlooked amid the violence in the country's east, where the M23 rebellion has conquered swathes of territory.