President Donald Trump made a series of cryptic remarks during a pre-dinner photo session with his top military advisers and their spouses Thursday night in the State Dining Room of the White House. As photographers snapped pictures and recorded video, Trump asked reporters: You guys know what this represents?" "Maybe it's the calm before the storm," he said, answering his own question. "What's the storm?" one reporter asked. "Could be the calm before the storm," he repeated. It was not immediately clear whether Trump was referring to one of a handful of thorny military or foreign policy areas - North Korea, the fight against ISIS, Iran's nuclear program, or the recent deaths of three U.S. soldiers in Niger - or simply making a joke. "We have the world's great military people in this room, I will tell you that. And uh, we're gonna have a great evening, thank you all for coming." "What storm, Mr. President?" NBC News' Kristen Welker asked again. "You'll find out," Trump replied, before reporters were ushered out of the room. NBC News has reached out to the White House for comment. In remarks to military leaders at the event, Trump thanked them and spoke of "pressing national security issues facing our country," according to an official White House transcript. The mystery continued into Friday. Trump, asked again during a brief session with U.S. manufacturers what he meant the night before, said only that "you'll find out" and winked.