The top U.S. diplomat on North Korea has warned that not solving the issue of weapons of mass destruction on the Korean Peninsula today could result in "an Asia-Pacific nuclear weapons challenge tomorrow," in a speech where he offered up the most detailed explanation to date of the Trump administration's strategy to rid Pyongyang of its nuclear arsenal.

In his first public speech since taking the post of U.S. special representative for North Korea five months ago, Stephen Biegun also revealed during an address Thursday at Stanford University in California that North Korea has promised to destroy all of its facilities for enriching uranium and plutonium — not merely its Nyongbyon site as previously announced — in exchange for "corresponding measures" to be discussed at working-level talks next week.

Biegun said that in addition to earlier commitments to dismantle two key missile and nuclear sites, North Korean leader Kim Jong Un had "also committed ... to the dismantlement and destruction of North Korea's plutonium and uranium enrichment facilities. This complex of sites that extends beyond Nyongbyon represents the totality of North Korea's plutonium reprocessing and uranium enrichment programs."