ALBUQUERQUE, N.M. (AP) — The head of the U.S. agency that maintains the nation’s nuclear weapons arsenal says the country is facing the most complex and demanding global security environment since the Cold War.

National Nuclear Security Administration chief Lisa Gordon-Hagerty spoke Tuesday at a business expo in New Mexico.

She said that Russia and China are investing significant resources to upgrade and expand their capabilities, Iran has increased its nuclear stockpile beyond limits set by a 2015 accord and North Korea’s intentions remain unclear.

She described the United States’ nuclear program as the “ultimate insurance policy.”

Gordon-Hagerty’s visit comes as the NNSA faces pressure to ramp up production of plutonium pits at facilities in New Mexico and South Carolina. The pits are key components for nuclear weapons.