Hours after President Trump said the United States would buy Russian diesel, the Kremlin said there would be no immediate resumption of discussions to end the war.President Trump on Saturday accused Ukraine of causing a “world problem” with Russian refinery attacks and said it should “get a new president,” further undermining Kyiv a day after saying he would open U.S. markets to Russian diesel. Speaking to reporters at the White House on Saturday, he said the United States had told Ukraine, “you can do whatever you want to Russia. Don’t hit the refineries because that’s a world problem that’s caused.”...