BANGKOK (AP) — The U.S. special envoy for North Korea has expressed hope that Pyongyang would accept Secretary of State Rex Tillerson's diplomatic offer of unconditional talks, although the overture has already been contradicted by the White House.

Joseph Yun told reporters in Bangkok on Friday that the talks could take place without preconditions and would serve Washington's dual approach of pressure and engagement on Pyongyang over its nuclear program.

Yun says it's unclear whether North Korea is willing to talk following a period of accelerated nuclear activity, saying "it's very hard to discern what their intent is without having real dialogue."

The White House has contradicted Tillerson's offer of talks without preconditions, saying North Korea must first take "sincere and meaningful actions toward denuclearization."