DRC president urged the pullout to begin by the end of this year, rather than December 2024 as planned.
Karti was foreign minister from 2010 to 2015 in the government of now-deposed dictator Omar al-Bashir.
They however argued that the matter of funding must now be urgently addressed to providing certainty to their stay.
Kenya Ports Authority data shows total cargo at the port was flat last year, falling by 1.94 percent to 33.88 million metric tonnes.
Scholars say the reshuffle at the Ministry of Foreign Affairs illustrates a major policy shift in Rwanda's regional policy.