Evidence

One search found a Kyiv Post article, "War Centers on Donbas, Can Only End Through Diplomacy, Rubio Says". It reports that at a press conference on Oct. 22 Rubio said the war is fundamentally about the Donbas. It also says Rubio described Donbas as an area Russia cannot seize militarily and Ukraine refuses to cede, and that he called for diplomacy and concessions from both sides. The Kyiv Post's own framing is ambiguous about the 11 percent figure. Its summary describes Donbas as roughly 11 percent "of the country", not 11 percent of Donbas. The claim's wording ("11 percent of Donbas it does not control") may therefore be a garbled version of what was said. I could not retrieve a transcript or a second outlet. A follow-up search hit the tool limit. I found no Reuters, AFP, Bellingcat or EUvsDisinfo fact-check on this claim.