ABOARD AIR FORCE ONE (AP) — President Donald Trump declined to say Friday whether he plans to resume underground nuclear detonation tests, as he had seemed to suggest in a social media post this week that 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,” without elaborating when asked if he means to resume underground nuclear detonation tests.

Defense Secretary Pete Hegseth offered few details on Friday when asked about what nuclear testing the Pentagon would oversee. But he seemed to indicate to reporters that the intent was to test warheads when he said “resuming testing” would be “pretty responsible.”

Trump, who spoke to reporters aboard Air Force One as he headed to Florida for a weekend stay, 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 then refused to offer more details.

His comments on nuclear testing have drawn confusion inside and outside the government when the president seemed to suggest in a brief post that the U.S. would resume nuclear warhead tests on an “equal basis” with Russia and China, whose last known tests were in the 1990s. Some of Trump’s comments seemed to refer to testing missiles that would deliver a warhead, rather than the warhead itself. There has been no indication that the U.S. would start detonating warheads.

The U.S. military already regularly tests its missiles that are capable of delivering a nuclear warhead, but it has not detonated the weapons since 1992. The Comprehensive Nuclear Test Ban Treaty, which the U.S. signed but did not ratify, has been observed since its adoption by all countries possessing nuclear weapons, North Korea being the only exception.

The Pentagon has not responded to questions. The Energy Department, which oversees the U.S. nuclear stockpile, declined to comment Friday.