DRC's president "In response to the strong demand from the youth, I invite them to organize themselves into vigilance groups with a view to propping up, accompanying and supporting our armed forces".
President Tshisekedi also renewed his call for young people to enlist in the army, while cautioning against "stigmatization of Rwandophone communities."
Tshisekedi repeated in an address broadcast on national television that the M23 operated with "the support of Rwanda", which he accused of harboring "expansionist ambitions".
A mostly Congolese Tutsi group, the M23 resumed fighting in late 2021 after lying dormant for years, accusing the Democratic Republic of Congo's government of failing to honour an agreement to integrate its fighters into the army.
The group's resurgence has destabilized regional relations in central Africa, with the DRC accusing its smaller neighbour Rwanda of backing the militia.
Tshisekedi said Rwanda had set its sights on "appropriating our minerals."
"To do this, it is working to destabilize eastern Congo to create a lawless zone to satisfy its criminal appetites," he said.
He added that diplomatic efforts to ease tensions have not led to "any tangible result."
The M23 went back on the offensive in late October after several weeks of calm, grabbing multiple localities along an important road serving the strategic eastern city of Goma.
The DRC announced on Sunday that it was expelling Rwanda's ambassador, while also recalling its own envoy from Kigali earlier this week.