"It remains to be seen when and how (North Korea) will return to the six-party talks," the U.S. official said in Seoul Thursday after his trip to try to persuade North Korea to resume the stalled six-nation talks.
"This is something that will require further consultations among all six of us," Bosworth said, referring to China, the United States, Russia, the two Koreas and Japan, Yonhap news agency reported.
On Friday, North Korea said it had reached an understanding with the United States on resuming the six-nation talks on its denuclearization.
The official Chinese news agency Xinhua said Bosworth's discussions within the framework of the six-party talks focused on ways to move forward on the verifiable denuclearization of the Korean Peninsula, and implementation of the other elements of the 2005 agreement.
The report quoted Bosworth as saying he communicated U.S. President Barack Obama's view that "complete denuclearization of the Korean Peninsula is the fundamental undertaking of the six-party talks, if resumed."
Xinhua quoted some South Korean experts as saying it was too early to say if Bosworth's trip was a success.
Korea University professor Yoo Ho-yeol said the dialogue was "not bad," as it did not cause any new troubles.
U.S. Secretary of State Hillary Clinton said Bosworth's trip was "quite positive," noting the trip was for "exploratory talks, not negotiations," Yonhap reported.