The failure of U.S. President Donald Trump and North Korean leader Kim Jong Un to secure even a limited deal at their second nuclear summit means any breakthrough now depends on working-level talks that have made little progress since last year.

The sudden collapse of talks Thursday highlighted just how large the gulf between the two countries remains, experts said.

It also underscored that whatever chemistry Trump and Kim might have, it was not enough to overcome differences that the rushed pre-summit negotiations left unresolved.