Japanese and South Korean officials and nuclear experts are preparing to visit North Korea next week to monitor the disabling of the nuclear facilities in Yongbyon, sources close to the six-way talks on the North's denuclearization have said.

The monitors will join monitoring teams from the United States, China and Russia who are already in place to monitor the politically sensitive work in Yongbyon, the sources said.

Work to disable North Korea's three nuclear facilities began earlier this month after a denuclearization-for-aid deal was reached in the second phase the six party talks in February.