A heated dispute has broken out between Rwanda and neighbouring country Burundi over 40 bodies found in a lake, according to Reuters.

The bodies were found on the Burundian side of Lake Rweru, with some of the corpses wrapped in plastic whilst others were reportedly found bound up. The origins, identities and cause of death of the bodies remains unclear.

While offficials say that just six bodies were found, local fishermen claim that they saw "as many as 10 times that number." Both countries are denying any involvement and have instead blamed each other.

The corpses were discovered in August, and an inquiry has been carried out by a team of Burundian officials.

Announcing the results of the inquiry at a news conference yesterday (14 October), Valentin Bagorikunda, the Burundian general prosecutor leading the investigation, concluded that the victims were not Burundian citizens but Rwandan.

"In conclusion, following all the evidence we have, it appears that the bodies found in August came from Rwanda. This is corroborated by reports from Burundi security forces, and testimonies of farmers and fishermen from Rwanda and Burundi."

Burundi claims that the bodies must have floated down the Akagera river from Rwanda and ended up on the Burundian side of the river.

Rwanda has not commented on the findings of the Burundian investigation.

The United States called for both countries to find out what had happened to the bodies, urging a "prompt, thorough, impartial and concerted investigation".

Relations between the two Great Lakes countries has been tense in recent years. Paul Kagame, President of Rwanda, has been accused of involvement in the assassinations of exiled opposition figures as well as targeting Hutus allegedly involved in the genocide.

Security concerns have been growing in Burundi with elections due in June 2015. The country has been through decades of ethnic massacres and political instability. A 12-year civil war decimated the country, only ending in 2005.