JUBA, South Sudan (AP) — South Sudan’s army has accused Uganda’s army of making a “major incursion” into its territory that led to fighting in which two South Sudanese soldiers were killed. Uganda’s military confirms an “incident” between the two armies but says it happened within Uganda.

South Sudan in a statement alleged that the Ugandan military crossed the border Tuesday in Magwi county in Eastern Equatoria state with heavy artillery and forced the small number of South Sudanese forces there to retreat. A counterattack regained control of the area, the statement said, but one South Sudanese soldier was captured.

South Sudan’s army reiterated its “cordial relations” with Uganda forces but said it was “saddened by chameleonic behaviors of that army,” spokesman Lul Ruai Koang wrote.

He later told The Associated Press that the Ugandan side also saw deaths. He also accused Ugandan forces of killing several other South Sudanese soldiers in two confrontations earlier this year.

Ugandan military spokeswoman Brig. Flavia Byekwaso told the AP that “yes, there was an incident” but it happened within Uganda. She asserted that Ugandan forces responded to an incursion by South Sudanese forces who “harassed” local people, and an exchange of fire ensued.

She gave no more details, saying the neighbouring countries are investigating and seek to resolve the issue through diplomatic channels.

The two countries have had border disputes in other areas along their border, but Byekwaso said this incident was not one of them.

Uganda supported South Sudan’s government during its recent five-year civil war and helped to broker a fragile peace. Uganda also has been accused by watchdogs of supplying South Sudan’s military in violation of arms embargoes. Uganda has denied it.