A Treasury Department analysis indicates that new U.S. sanctions on Russian oil producers have sent prices there tumbling, choking off a key revenue source that Russia has used to fund its war in Ukraine, the department said. One key benchmark for Russian oil prices — Urals crude — had fallen by at least 21% since a set of new sanctions were announced last month, a Treasury official said Thursday. The official also pointed to a decrease in the amount of oil departing from Russia to unknown