BRUSSELS — NATO Secretary-General Mark Rutte declined to say Thursday whether U.S. President Donald Trump had repeated his threat to quit the military organization, saying only that the U.S. leader was disappointed in some allies for being too slow to help with the Iran war. Rutte’s remarks came a day after he weathered a fresh ordeal with the U.S. leader, following months of tensions over Trump’s threats to seize Greenland. The U.S.-Israel war on Iran does not involve the world’s biggest military alliance and NATO allies were not consulted about it, but Trump has criticized fellow treaty members for their...