President Donald Trump has declined to say whether he plans to resume underground nuclear detonation tests. He had seemed to suggest that was a possibility in a social media post this week. The post raised concerns the U.S. would begin testing nuclear weapons for the first time in three decades. The president told reporters, "You'll find out very soon" when he was asked about it. Trump said, "We're going to do some testing" and "Other countries do it. If they're going to do it, we're going to." But he refused to offer more details. He spoke aboard Air Force One as he headed to Florida on Friday for the weekend.

President Donald Trump has appeared to suggest on social media that the U.S. resume testing nuclear weapons for the first time in three decades. There was no indication that the U.S. would start detonating warheads, but the president offered few details about what seemed to be a significant shift in U.S. policy. He made the announcement on social media minutes before meeting with Chinese leader Xi Jinping on Thursday in South Korea. The U.S. military already regularly tests its missiles that are capable of delivering a warhead, but it has not detonated the weapons since 1992 because of a test ban.