Bosworth, U.S. special representative for North Korea policy, was accompanied by U.S. Ambassador Sung Kim, who represents the United States at the so-called six-party talks on North Korea's nuclear program, CNN reported.
The American delegation will have talks in Seoul, Tokyo and Beijing, the U.S. State Department said. The discussion come as tensions grow between the Koreas, with South Korea blaming North Korea for the deadly sinking of a South Korean warship in March. North Korea denies it sank the ship.
The on-again, off-again nuclear discussions are among the Koreas, China, Japan, Russia and the United States.