A clash between Rwandan soldiers and DR Congo police on a small island in Lake Kivu sparked panic given ongoing tensions between Kigali and Kinshasa, Congolese sources said Sunday.

Police stationed on Ibindja island in eastern Congo, on the south side of the lake which the neighbours' border bisects, challenged three boats carrying armed Rwandan troops as they approached their base on Saturday, a DRC navy source based in the region said on condition of anonymity.

According to the source, a DRC policeman went to challenge the soldiers as to why they were on the Congolese side of the border.

After a discussion, "voices were raised and there were exchanges of gunfire," sparking panic among locals in earshot in Chivumu village.

Several families fled the island and took refuge just across the water at Birava, local civil society representative Jackson Kalimba said.

Naval sources said the Rwandan troops returned to base without disembarking on the island and Archimede Karhebwa, DRC local assistant administrator, said the situation was under control Sunday.

He said one police officer had suffered a gunshot wound and added the local naval regiment was on alert pending military high command taking "measures to reinforce surveillance of Lake Kivu".

Rwandan authorities contacted by AFP had not commented on the spat by Sunday afternoon.

Relations between the neighbours have been tense owing to the recent resurgence of the Tutsi-led rebel group M23.

The group has pledged to retreat from conquered territories after months of advancing towards Goma, capital of the DRC province of North Kivu at the northern end of the lake and likewise bordering Rwanda.

Kinshasa accuses Kigali of backing the rebels, which Rwanda denies.