KIGALI, Rwanda (AP) — Rwanda’s military on Tuesday said it had killed a Congolese soldier who crossed the border and allegedly fired at Rwandan army patrols, the latest incident in cross-border tensions between the neighbors.

In a statement, the Rwanda Defense Force said it also arrested two Congolese soldiers who had been with the one killed. It said they crossed the border at Isangano village in Rubavu district, near the Congolese city of Goma.

A local farmer, who spoke on condition of anonymity because of fear of reprisals, told The Associated Press the Congolese soldiers appeared to have crossed into Rwanda unknowingly, as some border markings can be difficult to see.

For months, Congo’s government has accused Rwanda of supporting the M23 armed rebel group that’s been active in eastern Congo, forcing hundreds of thousands of people to flee their homes. Rwanda has repeatedly denied the claim.

In March last year, the Rwandan army shot dead a soldier from Congo whom it alleged had crossed the border and shot at Rwanda Defense Force soldiers in Rubavu district. The incident led to an exchange of fire between soldiers from the two countries but no further casualties were reported, the force said.

President Félix Tshisekedi, while campaigning for his re-election last month, alleged that Rwandan President Paul Kagame was behaving like “Hitler,” which Rwanda’s government described as “a loud and clear threat.”

Relations between Rwanda and Congo have been fraught for decades. Rwanda alleges that Congo gave refuge to ethnic Hutus who carried out the 1994 Rwandan genocide that killed at least 800,000 ethnic Tutsis and moderate Hutus. In the late 1990s, Rwanda twice sent its forces into Congo. The Rwandan forces were widely accused of hunting down and killing ethnic Hutu, even civilians. Rwanda denies it.