In the violence overnight Wednesday, three soldiers, six militia fighters and two civilians were killed in Ituri province, the UN Radio Okapi reported.

"Ten people were seriously wounded, among them six militia members and four soldiers," the report said late Thursday.

The Front for Patriotic Resistance in Ituri (FRPI), one of many rebel movements active in eastern DR Congo, signed a peace accord with the government on February 28 this year, in the presence of the United Nations.

The accord provided for a ceasefire and the integration of FRPI fighters into the army, with draft legislation to give an amnesty to the rebels except in cases of war crimes or crimes against humanity.

Under the deal, the militia members -- several hundred men -- have since been confined to their quarters awaiting their transfer to the armed forces (FARDC).

The overnight battle is believed to have broken out when FARDC soldiers opened fire to disperse FRPI fighters who attempted to attack a military command post.

The FRPI has remained active since ethnic conflict took tens of thousands of lives in Ituri between 1999 and 2003, until a European military force named Operation Artemis intervened under French leadership.

One of the militia's leaders, Germain Katanga, was released from prison in March, after the International Criminal Court reduced a 12-year sentence imposed in 2014 for a conviction on war crimes and crimes against humanity.

Katanga was serving his term in DRC's capital Kinshasa after being repatriated from the ICC in The Hague in 2015.

A region rich in gold bordering Uganda and South Sudan, Ituri is wracked by a separate conflict in the northern Djugu territory, which has left about a thousand people dead since December 2017.