A four-week conference at the United Nations to review the treaty to prevent the spread of nuclear weapons has ended without an agreement as the United States and Iran spar over Iran's nuclear program.

The last remaining nuclear arms pact between Russia and the United States is set to expire this week, removing any caps on the two largest atomic arsenals for the first time in more than a half-century.

The Trump administration has halted the firings of hundreds of federal employees who were tasked with working on the nation’s nuclear weapons programs.