万斯：停火进展起伏不定 但俄方首次“显著让步”

Core Points - The U.S. Vice President Vance indicated that the negotiation process for a ceasefire between Russia and Ukraine has been inconsistent, but Russia has made significant concessions for the first time [1] - Vance noted that the U.S. has experienced both major progress and disappointment during negotiations with Russia, but he does not believe that Russia is "fooling" President Trump [1] - According to Vance, one of the concessions made by Russia includes agreeing to provide security guarantees for Ukraine [1] - Following a meeting with Russian President Putin, Trump threatened additional sanctions against Russia if there is no progress in peace efforts within two weeks [1] - This statement reflects the U.S. administration's frustration with Russia's attitude [1]