Rwanda and the Democratic Republic of Congo have agreed to co-operate to deal with forces along their common border blamed for the 1994 Rwandan genocide.
Both countries' foreign ministers said Rwandan intelligence teams would go into DR Congo to help eradicate them.
The Hutu fighters have lived in eastern DR Congo since 1994 and have been a key factor in destabilising the region.
Rebel leader Laurent Nkunda has made the disarmament of the Hutu forces a key demand to halting his rebellion.
Gen Nkunda says he is fighting to protect his Tutsi community from attacks by Rwandan FDLR Hutu rebels who fled to DR Congo after the genocide.
Some 250,000 people have fled violence that flared in August between Gen Nkunda's fighters and government forces.
The Congolese government has often promised to stop Hutu forces from using its territory, but has not done so.
Its forces have been accused of instead working with the FDLR to exploit the region's rich mines.
In last year's Nairobi agreement, the FDLR forces - estimated to number more than 6,000 - were meant to have been disarmed by the end of August.
The deadline was missed. At this point Gen Nkunda's forces resumed fighting.
But speaking at a joint news conference in the Rwandan capital, Kigali, the foreign ministers of Rwanda and DR Congo committed themselves to a course of action that correspondents say could change events in the region.
They agreed to Rwandan intelligence officers going into DR Congo to work with the Congolese army and the international community to help end the presence of the Hutu militia who have operated from the region's hills and forests.
"We confirm our firm will to bring a military plan, with man-power and material support from different countries, to enable us once and for all to put an end to the problem of the FDLR," DR Congo's Foreign Minister Alexis Mwamba Thambwe said.
Meanwhile, the UN says it is to move 60,000 people from a camp north of Goma to a location west of the city in case of fighting.
The people at Kibati camp are close to the front line separating government troops and rebels loyal to Gen Nkunda.
The UN refugee agency said aid workers have plotted out the new site - called Mugunga III - and most people will have to make the 15km journey there by foot.
Fighting has stopped aid from reaching Kibati and forced many there to flee south to the provincial capital, Goma.
The UN has accused both sides of war crimes during the latest upsurge in violence.
On Friday, women - some with black bin liners covering their hair - gathered at a sports stadium in Goma housing thousands of people who have fled the fighting.
They held up signs saying: "We mourn our children killed in Rutshuru" and "Enough of camp life".
"Women are tired of this war. We are just the victims. All people involved in this war are raping," one demonstrator, Solange Nyamulisa, told the BBC's Focus on Africa programme.
A spokesman for the charity ActionAid told the BBC that cases of rape and violence against women have risen dramatically since the latest fighting broke out.