A CNBC article reports Volodymyr Zelenskyy saying U.S. negotiators floated Ukraine ceding Donbas in exchange for NATO membership after U.S.-brokered talks with Russia in Abu Dhabi ended without a breakthrough — the first time the issue was raised, he says. Kyiv is not ready to concede territory but would put it to a referendum with security guarantees, and he dismisses Putin's proposed Kostiantynivka ceasefire, citing a 1,000-person prisoner exchange and Europe being given a seat at future talks.