The arrests come in a province that has been under military control since May 6 because of repeated attacks by an array of militia groups.

"We have arrested three senior officers suspected of inflating the troops numbers in Ituri," military prosecutor Joseph Makelele Mukenge told AFP.

President Felix Tshisekedi had recently denounced "the problem of the mafia, of schemes inside the armed forces," said Mukenge.

"We have to strike hard to put things in order," he added. He did not name the officers or give any further details on the charges against them.

But two other officers, including a colonel, are due to go on trial accused of losing military weapons, he said.

The trial of Colonel Jean-Lambert Munano Munangara and his deputy Bienvenu Ngwanga Podolo opens Friday at Bunia, the capital of Ituri province, according to court records consulted by AFP.

During a visit to Bunia on Saturday, Tshisekedi denounced what he described as criminal practices inside the armed forces and other Congolese institutions.

"A mafia has developed inside the army, inside our institutions", which the authorities would have to unravel, he said.

Ituri, on the border with Uganda, has suffered a surge in violence since December 2017, which military intervention has failed to stop. The ongoing conflict has claimed hundreds of lives.

Both Ituri province and North Kivu, just to the south, have been under military control since early May because of the insurgency.

According to the Kivu Security Tracker (KST), a US-headquartered NGO that monitors violence in the region, there are some 120 armed groups operating in the region.