As part of broader negotiations to end Vladimir Putin's war in Ukraine, the United States and Russia are considering the possibility of American companies returning to the Russian oil market.According to persons acquainted with the situation, the White House and the Kremlin have indicated that once the war is over, a joint venture including US and Russian oil companies may resume off the coast of Sakhalin, a Far Eastern island.They were also discussing incorporating the American majors in a plan to resume Russian oil deliveries to Europe through the Druzhba pipeline, they said.The potential accords are part of a larger US effort to terminate Putin's full-scale invasion, which is now in its fifth year, by offering incentives to return to the negotiating table. US leaders have frequently declared that the ventures would not begin until the conflict was done.