South Korea's top nuclear envoy Wi Sung-lac and his Japanese counterpart have agreed to watch bilateral talks between the United States and North Korea.

Wi on Sunday visited Japan to meet with Tokyo's chief delegate to the six-party talks Akitaka Saiki and reached the agreement.

The two officials also agreed to realize the North's nuclear disarmament through the six-party nuclear talks and to closely cooperate with Washington for a swift resumption of the talks.

Wi reportedly explained to Saiki the results of his recent meeting with Deputy Secretary of State James Steinberg.