A senior U.S. defense official said that the U.S. may need to adjust its nuclear force posture if China, Russia and North Korea continue to advance their nuclear capabilities. 

Vipin Narang, the acting assistant secretary of defense for space policy, made the remarks on Thursday during a forum hosted by the Center for Strategic and International Studies(CSIS), saying that the U.S. is in a new nuclear age with multiple revisionist nuclear challengers. 

Narang said that the nuclear challengers like China, Russia and North Korea have no interest in arms control or risk reduction efforts, are rapidly modernizing and expanding their respective nuclear arsenals, and are openly threatening to use nuclear weapons to achieve their aims.

The Pentagon official said that these challengers’ actions have forced the U.S. to shift to a more competitive approach that requires the U.S. to field a modern nuclear deterrent and to strengthen its network of allies and partners and extended deterrence efforts in NATO and the Inco-Pacific. 

Nagang added that absent a change in the nuclear threat trajectories of China, Russia and North Korea, Washington may reach a point where "a change in the size and posture" of its current deployed forces is necessary.