South Korea will use sanctions against North Korea until they succeed in discouraging Pyongyang's development of nuclear weapons, its foreign ministry said Friday.

The pledge comes two days after North Korea test-fired two intermediate-range ballistic missiles in defiance of international sanctions designed to deter its development of nuclear weapons and their delivery systems.

"We will consistently implement sanctions against North Korea over a sufficient timeframe until they have an effect, based on examples like that of Iran," the ministry said in a report to the National Assembly's foreign affairs and unification committee.

"We will continue to encourage the faithful implementation of U.N. Security Council resolutions, strengthening the standalone sanctions by key states, and the international community's pressure on the North," it said.

In March, the Security Council slapped the toughest yet sanctions on the North in response to its fourth nuclear test and its long-range rocket launch early this year. The ministry pledged a swift and firm response should Pyongyang carry out a fifth nuclear test or other provocations, citing the possibility of harsher sanctions.

Dismissing calls for dialogue with Pyongyang, it also reaffirmed the principle that denuclearization will be the focus of its policy on the North. (Yonhap)