The government is considering measures after confirming that North Korea stopped operations at a nuclear reactor in a possible move to reprocess spent fuel into plutonium.

Pyongyang said it will remove spent fuel rods from a five-megawatt reactor in Yongbyon, north of Pyongyang, over three months starting this month as part of its regular replacement of such rods.

Selig Harrison, a U-S expert who recently visited the North, said the unloading will provide some eight thousand spent rods that can be reprocessed into enough plutonium to produce six to eight nuclear bombs.

South Korea is downplaying the amount of plutonium North Korea can extract, and is instead focusing more on the political meaning of Pyongyang's claim to double its nuclear arsenal. The government is concerned that the North's move will further worsen the nuclear issue.

Joint measures by the parties of the six-way talks will likely be timed with visits to South Korea, China and Japan next week by Christopher Hill, the chief U-S negotiator to the talks.