In his announcement, Trump said the US had more nuclear weapons than any other country – a statement that does not match figures updated regularly by another think tank that specialises in the field, the Stockholm International Peace Research Institute (Sipri).
According to Sipri, Russia has 5,459 nuclear warheads followed by the US with 5,177, and China coming a distant third with 600.
Other think tanks reported similar numbers.
Russia announced recently it had tested new nuclear weapons delivery systems – including a missile the Kremlin said could penetrate US defences and another that could go underwater to strike the US coast.
The latter claim may have led to Trump’s announcement, some of the experts suspected, even though Russia said its tests “were not nuclear”.
Meanwhile, the US has been watching China closely – with increasing concern that it will reach near-peer status, too, and posing a “two-peer nuclear risk”, experts said.
So a resumption of US nuclear testing could prompt China and Russia to do the same.
A Kremlin spokesman said that “if someone departs from the moratorium, Russia will act accordingly”.
In its response, China said it hoped the US would fulfil its obligations under the Comprehensive Nuclear-Test-Ban Treaty – which both countries have signed but not ratified – and honour its commitment to suspend nuclear testing.
Daryl Kimball, executive director of the Washington-based Arms Control Association, said a US resumption of nuclear weapons testing would be “a mistake of historic international security proportions”.
He said the risk of nuclear conflict “has been steadily rising” over several years and, unless the US and Russia “negotiate some form of new constraints on their arsenals, we’re likely going to see an unconstained, dangerous, three-way arms race between the US, Russia and then China in the coming years”.
Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, said the average person should be “very concerned” because there has been an increase over the past five years in nuclear warheads for the first time since the Cold War.
The last US nuclear weapons test – underground in Nevada – was in 1992.
Kimball said it would take at least 36 months to get the Nevada site ready for use again.
The US currently uses computer simulations and other non-explosive means to test its nuclear weapons, and therefore does not have a practical justification to detonate them, multiple experts said.
Kwong said there were inherent risks even with underground testing, because you must ensure there is not a radioactive leak above ground and it does not affect groundwater.
While blaming Russia and China for ratcheting up the rhetoric, Robert Peters, senior research fellow of strategic deterrence at the conservative Heritage Foundation, said that, while there may not be a scientific or technical reason for testing a warhead, “the primary reason is to send a political message for your opponents”.
“It may be necessary for some president, whether it’s Donald Trump or whomever, to test nuclear weapons as a demonstration of credibility”, he said, arguing it was “not an unreasonable position to hold” to be prepared to test.
While many others the BBC spoke to disagreed, all offered a fairly dire assessment of the current situation.
“My sense is that, if the new nuclear arms race hasn’t already begun, then we’re currently heading towards the starting line,” said Rhys Crilley, who writes on the subject at the University of Glasgow.
“I worry every day about the risks of a nuclear arms race and the increasing risk of nuclear war.”
The US tested the first atomic bomb in July 1945 in the desert at Alamogordo, New Mexico.
It later became the only country in the world to use nuclear weapons in warfare after dropping two atomic bombs on the Japanese cities of Hiroshima and Nagasaki in August of the same year during World War Two.