The US federal government shutdown, which has forced the Department of Energy to place 1,400 staff of the National Nuclear Security Administration (NNSA) on unpaid leave, may hinder the country from achieving its nuclear weapons production goals, sources told CNN.

According to the sources, the remaining staff continues to work under conditions in which President Donald Trump’s administration is demanding that the Pentagon receive faster delivery timelines for modernized weapons from the NNSA.

CNN sources note that even a short halt in production can delay weapons creation by months or even years, as safely pausing work with nuclear materials is a complex process. Sources say the Trump administration’s actions directly contradict its ambitious national security objectives.

Under US law, departments and agencies responsible for national security and foreign policy continue to operate even during a federal government funding termination. Similar requirements apply also to civil servants whose work is aimed at protecting life and property. Employees of those state institutions who are obligated to work under such conditions do not receive pay immediately, but are usually compensated once funding is restored.