The U.S. military must be prepared as North Korea continues to pursue nuclear, chemical and biological weapons, a high-level Pentagon official told a House Armed Services subcommittee hearing.

In a statement delivered Tuesday, U.S. Principal Deputy Assistant Secretary of Defense Jennifer Walsh stressed the need to “be ready” to respond to contingencies should North Korean leader Kim Jong Un seek to use these weapons.

“North Korea’s continued pursuit of nuclear, chemical and biological weapons jeopardizes international stability and weakens the global nonproliferation regime,” wrote Walsh, warning that American joint armed forces should be ready if Kim Jong Un “[seeks] to