Washington is asking North Korea to respond to its proposal for gradual dismantlement of Pyongyang's nuclear program, ahead of a next round of the six-way talks slated for September.
U.S. State Department Spokesman Adam Ereli made the comments in regular briefing Saturday, saying that the U.S. has yet to hear from the North after having conveyed proposal in the previous round of six-party talks in Beijing.
The U.S. proposed in the June talks that North Korea be given a three-month period to prepare for eventual scrapping of its nuclear weapons programs. It also suggested an energy aid package for the North if Pyongyang were to proclaim its intention to abandon its nuclear ambition.