华盛顿软硬兼施，莫斯科释放信号，普京与美特使谈了3小时

Group 1 - The core point of the articles revolves around the ongoing discussions between Russia and the U.S. regarding the Ukraine crisis, particularly focusing on the potential for a ceasefire agreement and the implications of U.S. sanctions on Russia [1][2][3] - U.S. Special Envoy Wittekov's visit to Russia is significant as it marks the fifth time he has met with Russian President Putin since Trump took office, indicating ongoing diplomatic efforts despite rising tensions [1][3][4] - The discussions included considerations of a "air ceasefire" agreement, which may involve halting missile and drone attacks, although Russia is unlikely to agree to a full ceasefire [4][5][6] Group 2 - The U.S. has recently approved approximately $200 million in military aid to Ukraine, with four European countries also announcing over $1 billion in military support, indicating a strategy to increase pressure on Russia [3][5] - The deadline of August 8 set by Trump for Russia to reach a peace agreement with Ukraine is seen as a critical point, with potential sanctions looming if no agreement is reached [1][5][6] - There are concerns that imposing secondary sanctions on Russia could negatively impact the U.S. economy, particularly through increased inflation and higher import costs for American companies [7]