Divide and conquer? Maybe not, but North Korea's "charm offensive" and leader Kim Jong Un's invitation to South Korean President Moon Jae-in to visit Pyongyang "in the near future" will exacerbate existing fissures in Washington's alliance with Seoul as Pyongyang seeks to further chip away at the relationship.

Kim, using the grand stage of the Pyeongchang Winter Olympics, was behind Saturday's offer to host Moon for talks in the North Korean capital, setting the stage for what would be the first meeting of Korean leaders in more than a decade. The personal invitation from Kim was delivered verbally by his younger sister, Kim Yo Jong, during talks and a lunch Moon hosted at the presidential Blue House in Seoul.

Any meeting would represent a diplomatic coup for Moon, who swept to power last year on a policy of engagement with the isolated North while pursuing a diplomatic solution to the standoff over its nuclear and missile programs.