The ex-president has been equally withering in private, according to sources that either spoke to Kabila directly or had knowledge of his recent exchanges with opposition politicians and civil society members.
One source who spoke to Kabila said the message was that "the Tshisekedi regime is soon over".
"We will see what they do," said the source, who did not wish to be named due to the sensitivity of the discussions.
### TRANSITION BROACHED
All the sources said that, while Kabila and his lieutenants had spoken about some kind of political transition, there was no clear plan or details about how this might potentially unfold.
The talks have been private, though Kabila met openly in December in Addis Ababa with opposition leaders Moise Katumbi and Claudel Lubaya.
Asked for comment on Thursday on Kabila's reported outreach to the opposition, a spokesperson for Katumbi, former governor of DRC's copper-rich Katanga province, referred Reuters to past statements criticising Tshisekedi.
Lubaya, for his part, told Reuters on Thursday: "The sky is grey and the outcome uncertain for the country since Tshisekedi seems more concerned with retaining his power than with finding a solution."