The U.S. reportedly offered a long-term plan to help North Korea develop a tourist area in return for denuclearization during recent working-level talks in Stockholm that ended with the North side walking out, according to a new report.

American negotiators had drafted a plan to help build up the Kalma tourist area, the South's Hankook Ilbo newspaper reported Saturday, citing an unidentified top South Korean diplomat. The report didn't say how the North Koreans responded to the offer, but chief nuclear negotiator Kim Myong Gil portrayed the U.S. as inflexible after the talks earlier this month, blasting the Americans for not giving up "their old viewpoint and attitude."

Experts have said the North has put a priority on having suffocating U.S.-led U.N. sanctions eased before taking further steps toward denuclearization. The administration of U.S. President Donald Trump has repeatedly said the North can only have access to "a bright future" when it first abandons its nukes.