"Minister Yoon has offered to resign. President Roh Moo-Hyun has yet to make a decision on whether to accept his resignation," presidential spokesman Yoon Tae-Young told AFP.

The spokesman did not elaborate on the reason for the defense chief's resignation offer or whether it was linked to the October 9 test. The defense ministry refused to comment.

Yonhap news agency, quoting an unnamed source at Roh's office, said Yoon offered his resignation late Monday when he met President Roh to report on the outcome of annual US-South Korean defense ministers' talks in Washington.

"I think I have wrapped up what I am supposed to do," Yoon was quoted as telling Roh.

Yoon told a group of South Korean journalists late Tuesday that the President had "just listened" to him, adding that he would be in office until early next month, according to Yonhap.

During the talks last Friday, Washington promised Seoul "assurances of firm US commitment and immediate support" in defense matters, while repeating the annual pledge to use the US nuclear umbrella to deter threats.

Yonhap said Yoon's resignation is likely to be accepted. It also said Roh was considering conducting a partial cabinet reshuffle next week which would also affect Foreign Minister Ban Ki-Moon.

Ban becomes the United Nations secretary-general on January 1.

Song Min-Soon, chief presidential security aide, and Vice Foreign Minister Yu Myung-Hwan were touted as strong candidates to replace Ban.

Yonhap said Yoon could replace Song or head the country's main spy agency, the National Intelligence Service.

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