File Photo: Members of the Uganda Peoples Defence Forces (UPDF) position themselves on the Ugandan side of the border town in Bunagana, Democratic Republic of Congo, while awaiting deployment. AFP
Guterres addressed a high-level meeting in Burundi of African nations that signed a UN-brokered accord in 2013 to promote stability and security in the mineral-rich but conflict-wracked nation.
He said the agreement forged a decade ago marked a turning point for cooperation in the often-turbulent region, but "the current crisis underscores how far we have to go".
"Despite our collective efforts, more than 100 armed groups -- Congolese and foreign -- still operate today and thus threaten the stability of the entire Great Lakes region," Guterres told the gathering of presidents and other senior leaders in Bujumbura.
"It is time for the violence to stop. I reiterate my call to all armed groups -- lay down your arms, immediately."
Armed groups have plagued much of eastern DRC for three decades, a legacy of regional wars that flared in the 1990s and 2000s.
One militia, the M23, has captured swathes of territory in North Kivu since taking up arms in late 2021 after years of dormancy.
Guterres said the resurgence of M23 had displaced hundreds of thousands of people, and called on all parties to respect pledges made in Nairobi and Luanda last year to end that conflict.
An East African regional military force has taken over some areas previously occupied by the M23 since December.
The DRC accuses its smaller central African neighbour Rwanda of supporting the M23, an assessment backed by US and French officials as well as UN experts.
But Rwanda has repeatedly denied supporting the Tutsi-led rebels, who are still present in North Kivu and occasionally clash with rival militias.
Both Rwanda and DRC are signatories to the Peace, Security and Cooperation Framework signed in Addis Ababa in 2013 and backed by the UN and African Union that was eventually endorsed by 13 nations.
Guterres said "constant and sincere" dialogue was the only path to compromise and a lasting peace for the volatile region.
"I therefore encourage the signatory countries... to redouble their efforts," he said.
Guterres also met with Burundian President Evariste Ndayishimiye on his arrival in the country on Friday.