So-called "Mobondo" attacked the village of Nguma at 5 a.m., army spokesman Sylvain Ekenge said, using a name for a militia from the Yaka community.

Four militants were killed while one soldier died from wounds, he said, giving a provisional toll.

"Reinforcements from Kinshasa are already in the area and mopping-up operations are underway," Ekenge added.

Alexis Mampa Mundoni, the mayor of Kinshasa province's Maluku district -- where Nguma is situated -- confirmed the death toll to AFP.

Nguma lies only about 75 kilometres (45 miles) from the centre of Kinshasa, the sprawling capital of the Democratic Republic of Congo.

The attack marks a spillover from a conflict in neighbouring Mai-Ndombe province, which erupted last year due to a dispute over customary tithes between the Teke and Yaka communities.

At least 300 people have been killed since last June in Mai-Ndombe, according to Human Rights Watch (HRW).

Attacks in the rural Mai-Ndombe are difficult to verify, however, and some observers argue that the death toll is probably much higher.

The latest incident follows another suspected "Mobondo" attack that killed nine people on Sunday in the village of Yosso, also in Kinshasa province.

The festering conflict in western DRC has been largely overlooked, with attention focused on the M23 rebellion that has conquered swathes of territory in the country's east.