整理：俄乌冲突最新24小时局势跟踪（7月31日）

Conflict Situation - Air raid alerts and explosions reported in Kyiv, Ukraine [1] - Ukrainian Defense Minister states they are "very close" to acquiring weapons capable of striking targets within Russia [1] - President Zelensky of Ukraine has approved key principles for a weapons agreement with the United States [1] - Russian Defense Ministry claims to have attacked Ukrainian armed forces' robotic systems warehouses and transportation infrastructure used for hostile purposes [1] - Russia's Defense Ministry reports heavy strikes on a training center in Chernihiv region using Iskander missiles [1] Other Developments - Poland is set to purchase assault breaching vehicles from the United States valued at $115 million [1] - The International Atomic Energy Agency reports no increase in radiation levels at the Zaporizhzhia nuclear power plant [1] - European natural gas prices are nearing a two-week high, with the U.S. threatening to penalize Russian energy buyers [1] - Russian presidential spokesperson claims the Russian economy has developed a certain level of immunity to sanctions [1] - The U.S. plans to establish a fund to accept allied contributions to ensure weapon deliveries to Ukraine while replenishing its own stock [1] - Senate Republican leader McConnell indicates readiness to push for sanctions against Russia if necessary [1]