整理：俄乌冲突最新24小时局势跟踪（5月20日）

Conflict Situation - The Russian Ministry of Defense announced that Russian troops have taken control of the eastern Ukrainian region of Novoluhanske [1] - Missile danger warnings have been issued in Sochi and Novorossiysk, according to Russian news agency [1] Negotiation Status - U.S. Vice President Vance acknowledged that negotiations regarding the Ukraine conflict have reached a stalemate [2] - Ahead of a call between Trump and Putin, leaders from the UK, U.S., France, Germany, and Italy discussed the Ukraine issue [2] - A spokesperson for the German government stated that Chancellor Merz is collaborating with the U.S. and Europe on sanctions against Russia, aiming to compel Russia to agree to an unconditional ceasefire [2] - In the Trump-Putin call, both sides expressed a positive tone, with Russia indicating a willingness to sign a memorandum with Ukraine for a ceasefire. Trump stated that negotiations for a ceasefire would begin immediately [2] - Ukrainian President Zelensky had discussions with Trump and leaders from France, Finland, Germany, Italy, and the EU, considering a high-level meeting involving Ukraine, Russia, the U.S., EU countries, and the UK, and expressed willingness to sign a memorandum with Russia for a ceasefire [2]