A call by President-elect Donald Trump for an expansion of the United States' nuclear capabilities has alarmed nonproliferation experts, who said a boost to the U.S. arsenal could fuel global tensions.
In a Twitter post Thursday, Trump said, "The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes" but gave no further details.
It was not clear what prompted his comment. Earlier the same day, Russian President Vladimir Putin said Russia needs to "strengthen the military potential of strategic nuclear forces."