Russia Sharply Expanding Nuclear Arsenal, Upgrading Underground Facilities

Since 2010, however, Russia, China, and North Korea have been engaged in steadily building up their forces with new nuclear arms and delivery systems, while Iran remains an outlier that many experts believe will eventually decide to build a nuclear arsenal in the next decade or sooner when restrictions outlined in the international nuclear deal expire.

The Pentagon's new posture review is based in part on a reversal of the outdated Obama-era assessment.

Russia's nuclear forces—new warheads, missiles, bombers, and submarines—are increasing sharply.

The nuclear modernization is regarded as more ominous because it is coupled to Moscow's new strategic doctrine that calls for quickly resorting to nuclear weapons during any conventional conflict.

The 8,000 nuclear warheads will include both large warheads currently deployed on long-range mobile missiles and missile-firing submarin