But relations became strained after they invaded Congo in 1998.
He accuses them of invading Congo and creating a rebellion that would otherwise barely exist.
Rwanda and Uganda, which invaded Congo in 1998, have already promised to begin pulling back as early as next week.
Although Western diplomats generally acknowledge that Rwanda and Uganda have invaded Congo, almost no one has publicly supported the Kabila government.
Northwestern Rwanda - a Hutu extremist stronghold - has been largely quiet since Rwanda invaded Congo.
Rwanda and Uganda then invaded Congo and worked to overturn President Kabila.
In recent months, Mr. Levitte said, a cease-fire has held; troops from Rwanda and Uganda, which invaded Congo in 1998, have been pulling back as promised.
In early October 1997, Angolan troops invaded Congo on the side of Sassou.
In the region, he antagonized his former allies, Rwanda and Uganda, which invaded Congo in 1998; by then they were aligned with Congolese rebels.
Rwanda's Tutsi-led government has invaded Congo three times in the last decade, ostensibly to root out rival Hutu extremists who roam Congo's eastern border.