Tshisekedi's warning comes after the arrest of his security adviser earlier this month fuelled speculation of division within the government or even suggestions of a coup attempt.

The Democratic Republic of Congo's army is carrying out several military operations in the east of the vast country, particularly in the strife-torn provinces of Ituri and North Ituri.

"Several cases of indiscipline have been observed at all levels of the military" command which "contributed to certain failures we experienced on the ground," Tshisekedi said Thursday.

Speaking during a ceremony to exchange vows with senior army and police officers, he also denounced "the poor management of funds and equipment made available to unit commanders at all levels."

"When the commanders think they can do well by enriching themselves and depriving our troops of the means which can help them more in their mission, it is betraying the republic."

"That is intolerable," he said, promising to be "tougher" from now on.

Tshisikedi also sent out a reminder that the army was "apolitical" and had a "duty of reserve".

"You are not here to engage in politics," he said.

"If you want to engage in politics, it's simple. You take off your uniform, you return to civilian life."

He promised to be "ruthless" towards crooked and recalcitrant officers.

The comments come after presidential security adviser Francois Beya was arrested on February 5 -- while Tshisekedi was out of the country -- and he has since been detained at the headquarters of the National Intelligence Agency.

Three days later the government said that "indications of serious actions against state security" were uncovered.

In a bid to stem the grinding violence in the east, last year Tshisekedi put Ituri and North Kivu under a "state of siege", a measure giving exceptional powers to the army and police.