South Korea on Monday said denuclearization should come first before any talks resume with North Korea, emphasizing that it is currently facing a "critical" moment that can determine whether to prevent Pyongyang's continued pursuit of nuclear weapons.

In a report to the National Assembly's foreign affairs and unification committee, the unification ministry said it will keep working on sanctions and pressure against the North to induce a change in its "strategic calculus."

"In response to the North's repeated nuclear and missile provocations, (we) will pursue its denuclearization and tangible changes as the top priority," the ministry said. "For its dialogue and exchange proposals, (we) will respond with a firm stance that denuclearization should come first."

The North is faced with sanctions led by the U.N. Security Council, which adopted its toughest-ever resolution in March to punish Pyongyang for its fourth nuclear and long-range ballistic missile tests earlier this year.