US President Donald Trump has claimed that Pakistan is among the countries currently testing nuclear weapons. His remarks came as reports suggested that the United States might resume its own nuclear tests after several decades.

Trump said that countries like Russia, China, North Korea, and Pakistan are carrying out nuclear tests, and therefore, it was “appropriate that the US also does it.”

"Russia's testing and China's testing, but they don't talk about it. We're an open society. We're different. We talk about it. We have to talk about it because otherwise you people are going to report. They don't have reporters that are going to be writing about it," Trump told CBS News.

"We're going to test because they test and others test. And certainly North Korea's been testing. Pakistan's been testing," he added.

Trump said the United States does not "necessarily know" where these "powerful" nations are conducting their tests, but believes the activity is taking place.

"They, they test way under, underground, where people don't know exactly what's happening with the test. You feel a little bit of a vibration. They test and we don't test. We have to test," he said.

He made these comments when asked about his decision to "detonate nuclear weapons" for the first time in more than thirty years, following Russia’s recent trials of advanced nuclear-capable systems, including the Poseidon underwater drone.

"You have to see how they work. The reason I'm saying testing is because Russia announced that they were going to be doing a test. If you notice, North Korea is testing constantly. Other countries are testing. We're the only country that doesn't test. And I don't want to be the only country that doesn't test," Trump said during the interview.

Trump also said the United States has "more nuclear weapons than any other country," and that he had spoken with Russian President Vladimir Putin and Chinese President Xi Jinping about denuclearisation.

"We have enough nuclear weapons to blow up the world 150 times," Trump said. "Russia has a lot of nuclear weapons, and China will have a lot. They have some. They have quite a bit."

US Energy Secretary Chris Wright later clarified that the planned testing will not include nuclear explosions. This was the first clarification from the administration after Trump said last week that he had "instructed the Department of War to start testing our nuclear weapons on an equal basis."

"I think the tests we're talking about right now are system tests. These are not nuclear explosions. These are what we call non-critical explosions," Wright said in an interview with Fox News.

He explained that the testing would focus on "all the other parts of a nuclear weapon to make sure they deliver the appropriate geometry and they set up the nuclear explosion."

Wright added that the new tests will be carried out on updated systems to ensure that replacement nuclear weapons perform better and more safely than previous versions.