Uganda on Saturday protested an incursion by Rwandan soldiers on its territory that it said resulted in two deaths, a development that could inflame already tense relations between the neighbours.
Two Rwandan soldiers entered Ugandan territory in the southwestern district of Rukiga on Friday in pursuit of a suspected smuggler, the Foreign Affairs Ministry said.
They shot dead a Rwandan and a Ugandan, it said.
"Uganda protests in the strongest terms the violation of its territorial integrity by Rwandan soldiers and the criminal, brutal and violent act by the Rwandan soldiers, on Ugandan territory against unarmed civilians," the ministry said in a statement.
"The ministry demands that action be taken against the perpetrators of this attack."
According to the ministry the soldiers entered Uganda while pursuing a Rwandan national suspected of smuggling merchandise. After the soldiers caught up with the man about 50 metres (yards) inside Ugandan territory, he resisted arrest and was then instantly shot. The soldiers then shot a Ugandan man who had attempted to intervene, the ministry said.
Rwanda's ambassador to Uganda, Frank Mugambage, was not immediately available for comment.
Relations between the countries have been strained since February over economic and political disagreements.
At the end of February, Rwanda started blocking Ugandan cargo trucks from entering at Katuna, the busiest crossing on the two nations' border. Authorities in Kigali also started stopping the country's nationals from travelling to Uganda.
Kigali accused Kampala of supporting rebel groups opposed to president Paul Kagame's government, including the Rwanda National Congress (RNC) and the FDLR.
Kampala has in turn accused Rwanda of effectively imposing a trade embargo on Uganda.
Rwanda depends for much of its imports on a trade route through Uganda to Kenya's Indian Ocean seaport of Mombasa. The same transport artery is also a pipeline for goods from Kenya and Uganda to Burundi and parts of eastern Democratic Republic of Congo.