The U.S. must modernize its nuclear force to remain on-par with near-peer adversaries Russia and China, a top Air Force general said Friday.

Lt. Gen. Stephen “Seve” Wilson, the deputy commander of U.S. Strategic Command, said the U.S. has no choice but to modernize and update its nuclear force if it wants to continue deterring other nations.

“Broadly, our nation and our Department of Defense stopped thinking about deterrence in 1992,” Wilson said during a breakfast meeting hosted by the Air Force Association’s Mitchell Institute in Washington, D.C. “We need a really credible and ready and resilient nuclear force; and we’re doing just that. The department is investing a lot of money across the five-year defense plan on our nuclear force.”

The Pentagon is facing a “bow wave” of nuclear modernization costs in the early 2020s, when experts expect much of the Defense Department’s budget will be taken up by replacing and upgrading air-, land- and sea-based nuclear capabilities.

Wilson argued that replacing existing equipment is a critical step in allowing the U.S. to maintain its nuclear deterrence. Russia is already working on building new intercontinental ballistic missiles and air-launched cruise missiles, and China isn’t far behind.

Read More: Defense News

Featured Image – An unarmed Minuteman III intercontinental ballistic missile launches during an operational test at 11:34 p.m., Feb. 20, 2016, Vandenberg Air Force Base, Calif. (U.S. Air Force Photo by Michael Peterson/Released)