The instability has forced more than 300,000 people to flee their homes with people escaping unrest in Djugu territory especially.
Democratic Republic of Congo's leader said Sunday he had ordered the army to launch a "large-scale" operation against armed groups in the restive east after the killings of scores of civilians.
"I've ordered our armed forces to carry out large-scale operations in the territories of Djugu and Mahagi" in the volatile Ituri province, President Felix Tshisekedi said Sunday in the capital Kinshasa.
He added that the offensive would extend to South Kivu province to put a "definite end" to the dozens of militias roaming the lawless, mineral-rich region, where millions of lives were lost in a 1998-2003 war.
The instability has forced more than 300,000 people to flee their homes, the UN refugee agency has said, with people escaping unrest in Djugu territory especially.
At least 160 civilians have died in Ituri since June 10, according to local authorities who blame the Ngudjolo militia for the violence.
The army announced last week it had taken control of the group's stronghold in an offensive backed by the UN peacekeeping mission MONUSCO.
In Sunday's speech, Tshisekedi said his government had devised a plan for the "complete eradication" of foreign armed groups, in collaboration with MONUSCO and neighbouring countries affected by the violence, particularly Uganda and Rwanda.
He also hailed the "easing of political tensions" since he took power in January, saying that political exiles had returned and that rallies were being held "without hindrance".
However, he attacked opposition leaders for trying to organise a banned march in Kinshasa on Sunday and accused them of "confusing democracy with anarchy".
His comments came as police firing tear gas blocked the planned march in Kinshasa, while security forces used tear gas to disperse small groups of protesters in Goma, the capital of North Kivu.
In addition to the violence, Ituri and North Kivu province are also trying to roll back a major epidemic of Ebola that has claimed more than 1,400 lives since last August. Both provinces sit on DR Congo's eastern border with Uganda.