The first round of working group nuclear talks will open on May 12th in Beijing.

A South Korean official said the two Koreas, the United States, Japan, China and Russia have agreed to convene the meeting to discuss technical details ahead of higher-level discussions on resolving an international standoff over Pyongyang's nuclear weapons ambitions.

The official said the six countries agreed not to limit the agenda for the negotiations and to hold discussions amid an unrestricted atmosphere with no date set for a closing day of the talks.

It is uncertain whether the working-level discussions will produce tangible progress in view of the differences in opinion between North Korea and the United States.

North Korea is sticking to its longstanding demand for economic incentives in return for its nuclear freeze while the U.S. is adhering to its call for Pyongyang to completely, irreversibly and verifiably dismantle its nuclear program first before any talks on compensation.

Meanwhile, Ning Fukui, China's envoy on the nuclear issue, is scheduled to visit Seoul Thursday and hold talks with senior Foreign Ministry officials.