The head of U.S. Strategic Command, which oversees the nuclear arsenal, warned Congress that Washington faces a heightened nuclear deterrence risk when it comes to Russia and China, DefenseNews reported.

“We are facing a crisis deterrence dynamic right now that we have only seen a few times in our nation’s history,” Adm. Charles Richard told the Senate’s strategic forces panel. “The war in Ukraine and China’s nuclear trajectory— their strategic breakout—demonstrates that we have a deterrence and assurance gap based on the threat of limited nuclear employment.”

“The nation and our allies have not faced a crisis like Russia’s invasion of Ukraine in over 30 years,” said Richard. “President [Vladimir] Putin simultaneously invaded a sovereign nation while using thinly veiled nuclear threats to deter U.S. and NATO intervention.”

He went on to note that China is “watching the war in Ukraine closely and will likely use nuclear coercion to their advantage in the future.”

Richard said China has doubled its nuclear stockpile within two years, despite expectations it would take Beijing until the end of the decade to do so.