Senior Russian military commanders recently held conversations to discuss when and how they might use a tactical nuclear weapon in Ukraine, The New York Times reports, citing multiple senior American officials.
The report says Russian President Vladimir Putin was not part of the discussions.
The report comes amid heightened tension and fears Russia could use nuclear weapons.
The US officials say Russian generals are becoming increasingly frustrated by their setbacks on the battlefield in Ukraine.
But the officials say they have seen no evidence so far that Russia has made practical efforts to move warheads into place for use.