The US has imposed its toughest sanctions yet on Russia's oil and gas revenues in an effort to give Ukraine leverage in reaching a peace deal. The sanctions target Gazprom Neft and Surgutneftegas, as well as 183 vessels that have shipped Russian oil. The move is expected to cost Russia billions of dollars per month if enforced. The sanctions will also cause severe disruption to Russian oil exports to major buyers India and China. The Biden administration has provided Ukraine with $64bn in military aid since the invasion, including $500m this week for air defense missiles and support equipment for fighter jets.