Washington (CNN) President Donald Trump would like the US to be "at the top of the pack" when it comes to having nuclear weapons.

The President said the US has "fallen behind on nuclear weapons capacity" and that, while he would like to see the lethal weapons abolished, as long as they exist "we're never going to fall behind on nuclear power." And he added that an agreement with Russia to limit nuclear arms is "a one-sided deal."

But experts describe America's nuclear program as strong and dominant, and worry about the implications of his comments.

"I know of no senior American military officer who says 'I would like to trade American nuclear forces with anybody else,'" said Steven Pifer, director of arms control and nonproliferation at the Brookings Institution, who said he and other experts are "just not sure where Trump's getting his information."

Here are some of the questions raised by his comments.

Does the US have nuclear supremacy already?

Experts -- and critics -- say no country can match the US for the strength, size or modernity of its nuclear weaponry.

In a January 2017 speech, Vice President Joe Biden said that as of September 30, 2016, the US possessed 4,018 active and inactive nuclear warheads and about 2,800 more warheads that were retired and awaiting dismantlement.

In September, under declarations required by the New Strategic Arms Reduction Treaty (START), Russia said it had 1,796 strategic warheads deployed on submarines, missiles and bombers. The Federation of American Scientists estimates Moscow has another 2,700 warheads -- both more powerful warheads that aren't deployed and smaller ones. The FAS estimates that Russia has another 2,510 warheads in line to be dismantled.

And while domestic critics say American nuclear weapons are old, that's not always a good measurement, according to Pifer. He pointed to failed Russian tests of newer weapons while the American Trident D5 missile succeeded in "all but two or three of its tests in the last 30 years," he said.

Paul Kawika Martin, senior director of policy and political affairs at Peace Action, a pro-peace advocacy group, said the US has "the most modern, safe and secure" nuclear arsenal in the world.

The amount of money Russia has been investing in its nuclear weapons, he said, is "infinitesimal compared to the amount of money the US is spending and planning to spend on what I call an escalation of nuclear weapons and the government calls modernization."

Isn't the US already modernizing its nuclear arsenal?

Yes. The US is working on a $1 trillion modernization of its submarines, bombers, ballistic and land-based missiles over the next 30 years.

Current US nuclear forces consist of submarines that launch ballistic missiles, land-based intercontinental ballistic missiles, long-range bomber aircraft, shorter-range tactical aircraft, and the nuclear weapons that those delivery systems carry, according to the Congressional Budget Office, the non-partisan research arm of Congress.

Those weapons are getting obsolete, according to CBO, and will have to be refurbished or replaced over the next two decades to keep operating. The CBO estimated the cost of operating, maintaining and modernizing US nuclear forces at an average of $40 billion a year over the next decade.

Martin, of Peace Action, said the cost creates one very basic challenge for the modernization program, particularly in a tight budget environment with an administration that says it's deficit conscious at a time when the New START Treaty requires both the US and Russia to curtail the number of warheads they have deployed.

"We can't afford this," Martin said. "Even hawks that want to fund the Pentagon much more than I would are saying, 'Why are we spending all this money on weapons we say we want to get rid of when we're short in other areas,' like force-readiness issues."

Exactly what is the New START Treaty?

Russia and the US signed the New Strategic Arms Reduction Treaty in 2010. The agreement, an upgrade on the 1991 START, commits both countries to scaling back their nuclear warheads by 2018.

Both countries are required to restrict the number of deployed warheads to 1,550 across 700 delivery systems, including intercontinental ballistic missiles, submarine-launched ballistic missiles and bombers.

The nonproliferation community and former Pentagon officials have praised the pact, Pifer noted, adding that it requires both countries to open up their missile sites for inspection, giving the US insight into Moscow's armaments that it wouldn't otherwise have.

"The Joint Chiefs of Staff endorsed it, a bunch of former Republican officials endorsed it," Pifer said. "We're all wondering why [Trump] said this treaty was one-sided."

Are his comments reassuring or provocative to other countries?

In the immediate aftermath of the Trump interview, Russian politicians allied with President Vladimir Putin reacted to the US President's comments with alarm, according to Reuters.

Many Russians had been hoping that Trump's praise of Moscow would mean friendlier relations between the two countries. Reuters quoted the chairman of the international affairs committee in the upper house of the Russian parliament saying that if Trump's campaign slogan, "Make America great again," means nuclear supremacy, it "will return the world to the worst times of the arms race in the '50s and '60s."

Martin said that countries such as North Korea, which has aggressively pursued a nuclear weapons program, and larger US rivals like China, watch closely to see what the US says and what it does, and make decisions about expanding their own arsenals accordingly.

"It's clear we're not moving away from nuclear weapons," Martin said. "Instead we say things like 'top of the pack' that convey that we're going to continue to get more or build more or invest huge amounts of money in our nuclear weapons systems. Statements have consequences and budgets have consequences."