A peace agreement brokered by the White House to stem the bloodshed in the eastern Democratic Republic of Congo was signed in Washington D.C. on Friday by officials of the two African nations.

The agreement marks a breakthrough in talks and intends to attract billions of dollars of Western investment to a region rich in cobalt, copper, lithium and other minerals.

A deal signed in Washington has been touted as a major step toward peace in Congo following decades of conflict that has killed millions, including thousands this year.