President Donald Trump is getting praise from his most ardent supporters for withholding some weapons from Ukraine after they recently questioned his commitment to keeping the U.S. out of foreign conflicts.

President Trump said on Thursday that a phone call with President Vladimir V. Putin of Russia had not resulted in any movement toward ending the war in Ukraine, adding that he was “not happy” with the conflict grinding on. “I didn’t make any progress with him at all,” Mr. Trump told reporters.