As the U.S. and North Korea enter a growing stalemate in negotiations over sanctions and denuclearization, Washington signaled Thursday it would not in the meantime approve sanctions exemptions for inter-Korean projects.

In a press briefing Thursday, a senior State Department official  -- believed to be Special Representative for North Korea Stephen Biegun -- also said the U.S. is waiting for North Korea to come back to the table for an all-for-all deal that would see complete denuclearization in exchange for sanctions relief and economic incentives, all achievable by early 2021, they said.