In continuing political fallout following North Korea's nuclear test, South Korea's principal envoy to Pyongyang is offering to step down from his Cabinet post.

Government officials in Seoul said Wednesday that Unification Minister Lee Jong-seok delivered his resignation offer directly to South Korean President Roh Moo-hyun on Tuesday. The president has not announced his response.

Lee pursued a policy of engagement with Pyongyang. During the two and a half weeks since North Korea detonated an underground nuclear explosion, the unification minister has been a target of criticism within South Korea, for allegedly being too "soft" on the reclusive communist state.

The South Korean government says its engagement policies remain intact, and that it will continue trying to encourage broader contacts with North Korea. At the same time, however, officials in Seoul pledge they will uphold sanctions against North Korea that have been ordered by the United Nations Security Council.

Lee was named unification minister in February, and he also served as President Roh's top security adviser. He is the second key member of Mr. Roh's Cabinet to speak of resignation this week -- following Defense Minister Yoon Kwang-ung's offer to step down, announced on Monday.

The president also must replace Foreign Minister Ban Ki-moon, who will be leaving the South Korean government soon to take up his new post as United Nations secretary-general.

Some information for this report was provided by AP, AFP and Reuters