US President Donald Trump said he wants America to be "top of the pack" when it comes to nuclear weapons arsenals.

With many fearful of the implications of what Trump means for nuclear warfare, the president said he is concerned about falling behind Russia's atomic stock.

Russia has 7,300 nuclear warheads in comparison with The US's 6,970 – according to anti-nuclear group the Ploughshares Fund – but Trump's comments could be seen as sparking a new Cold War.

In an interview with Reuters, Trump said: "I am the first one that would like to see everybody, nobody have nukes.

"But we're never going to fall behind any country even if it's a friendly country. We're never going to fall behind on nuclear power.

"It would be wonderful, a dream would be that no country would have nukes, but if countries are going to have nukes, we're going to be at the top of the pack."

Nuclear weapons experts derided the comments as poorly thought out.

Daryl Kimball, executive director of Arms Control Association, an independent non profit, said: "The history of the Cold War shows us that no one comes out 'on the top of the pack' of an arms race and nuclear brinkmanship.

"Russia and the United States have far more weapons than is necessary to deter nuclear attack by the other or by another nuclear-armed country."

Trump also discussed the current nuclear weapons treaty with Russia, known as New START, in which both countries must limit their nuclear arsenals to equal levels for 10 years by 5 February 2018.

"Just another bad deal that the country made, whether it's START, whether it's the Iran deal ... We're going to start making good deals," Trump said.

The comments were similar to those made during the 2016 presidential campaign in which Trump claimed Russia "outsmarted" the US with the treaty and incorrectly declared it allowed Russia to continue to produce nuclear warheads while the US could not.

Democratic senator Jeanne Shaheen, of the Senate Foreign Relations Committee, said it was incomprehensible how Trump did not understand the value of the treaty.

"It's impossible to overstate the negligence of the president of the United States not knowing basic facts about nuclear policy and arms control," she said.

"New START has unquestionably made our country safer, an opinion widely shared by national security experts on both sides of the aisle."