United States Secretary of State Condoleezza Rice is meeting ministers involved in six-nation talks on North Korea's nuclear disarmament, including a rare encounter with her North Korean counterpart.
The ministers are meeting on the sidelines of an annual Asia-Pacific regional meeting in Singapore.
China has described the meeting as "very significant", but the US says it will be an informal exchange of views.
It comes weeks after North Korea handed over data on its nuclear activities.
The discussions are expected to focus on how that information will be verified.
North Korea agreed in February 2006 to end its nuclear programme in return for aid and diplomatic concessions.