The State Department said Stephen Biegun would be in Moscow on Wednesday and Thursday "to meet with Russian officials to discuss efforts to advance the final, fully verified denuclearisation of North Korea."
The visit came with Russian, South Korean and Japanese media reporting that Kim and Putin may soon have their first summit, in Russia's Far East.
One of the sources warned that the plans could change, however, noting that Kim was an "impulsive person".
On Wednesday, the agency reported that North Korea's flagship carrier Air Koryo had scheduled a special flight to Vladivostok on Tuesday next week.
Japan's Jiji Press, quoting a Russian diplomatic source, said it was "99 percent" certain that Putin and Kim will meet next Wednesday in Vladivostok.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)