President Donald Trump sits for an interview in the Oval Office at the White House in Washington, February 23, 2017. Jonathan Ernst | Reuters

President Donald Trump said on Thursday he wants to build up the U.S. nuclear arsenal to ensure it is at the "top of the pack," saying the United States has fallen behind in its atomic weapons capacity. In a Reuters interview, Trump also said China could solve the national security challenge posed by North Korea "very easily if they want to," ratcheting up pressure on Beijing to exert more influence to rein in Pyongyang's increasingly bellicose actions. In his first comments about the U.S. nuclear arsenal since taking office on Jan. 20, Trump said the United States has "fallen behind on nuclear weapon capacity." "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," Trump said. The new strategic arms limitation treaty, known as New START, between the U.S. and Russia requires that by February 5, 2018, both countries must limit their arsenals of strategic nuclear weapons to equal levels for 10 years. The treaty permits both countries to have no more than 800 deployed and non-deployed land-based intercontinental and submarine-launched ballistic missile launchers and heavy bombers equipped to carry nuclear weapons, and contains equal limits on other nuclear weapons. Analysts have questioned whether Trump wants to abrogate New START or would begin deploying other warheads. In the interview, Trump called New START "a one-sided deal. "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," he said. The United States is in the midst of a $1 trillion, 30-year modernization of its aging ballistic missile submarines, bombers and land-based missiles, a price tag that most experts say the country cannot afford.